CN102569504B - For the method forming cadmium tin oxide layer and photovoltaic device - Google Patents

Abstract

The present invention relates to the method for forming cadmium tin oxide layer and photovoltaic device.In one aspect of the invention, it is provided that method.The method is included on supporter and arranges the cadmium tin oxide layer of generally amorphous and by the first surface of this generally cadmium tin oxide layer of amorphous is exposed to electromagnetic radiation, the cadmium tin oxide layer rapid thermal annealing of this generally amorphous formed clear layer.The method also providing for manufacturing photovoltaic device.

Description

For the method forming cadmium tin oxide layer and photovoltaic device

Technical field

The present invention relates to the method for forming photovoltaic device.More particularly it relates to use In the method forming polycrystalline cadmium tin oxide layer by rapid thermal annealing.

Background technology

Thin-film solar cells or photovoltaic device typically comprise and multiple are arranged on transparent supporting body On semiconductor layer, wherein one layer is served as Window layer, and the second layer serves as absorber layers.Should Window layer allows solar radiation to be penetrated into this absorber layers, and at this absorbed layer, luminous energy is changed Become available electric energy.Photovoltaic cell based on cadmium telluride/cadmium sulfide (CdTe/CdS) hetero-junctions It it is such example of thin-film solar cells.

Typically, the veneer of transparent conductive oxide (TCO) is in supporter and Window layer The function of pick-up current catcher before rising between (such as, CdS).But, such as fluorine doped oxygen Change the conventional TCO such as stannum, tin indium oxide and Al-Doped ZnO for good optical transmittance Under required thickness, there is high resistivity.Cadmium tin (CTO) is used as TCO to be provided more preferably Electricity, optically and mechanically character, and stability at elevated temperatures.But, base Thin-film solar cells in CdTe/CdS still has challenge, and such as thick CdS film is typically Due to the short circuit current (J reduced_SC) cause low device efficiency, but thin CdS film can cause Open-circuit voltage (the V reduced_OC).In some instances, in order to obtain high device with thin CdS film Part efficiency, the most unadulterated stannum oxide (SnO₂) thin layer of the padded coaming such as layer inserts oxidation Between cadmium stannum (CTO) and window (CdS) layer.

It is included in deposited amorphous cadmium tin on supporter for manufacturing the typical method of CTO layer Layer, is followed by the slow thermal annealing of CTO layer (it contacts with CdS film or closes on CdS film), Obtain desired transparency and resistivity.But, the annealing based on CdS of CTO is difficult to Mass-manufacturing environment realizes.Specifically, the most difficult group before and after annealing process Installation and dismantling solution plate, it typically requires that the manual intervention of operator, and exists and may cause The out-of-alignment excessive risk of CTO film distillation.Additionally, can use again non-for each annealing steps The CdS using costliness on glass plate increases manufacturing cost.Heat treatment for CTO film uses High annealing temperature (＞ 550 DEG C) do not allow to use relatively inexpensive low softening temperature to support Body, such as soda-lime glass etc..

After the crystallization obtaining CTO, separate cushion (such as, undoped p stannum oxide) Being deposited on CTO layer, it can obtain good knot further followed by the second annealing steps Crystalloid amount.The performance of this cushion generally depends in part on degree of crystallinity and the form of this layer, and Affected by the surface (this is deposited upon on CTO surface) of CTO.High-quality cushion for It is desirable for obtaining desired performance in the solaode thus manufactured.

Accordingly, there are and reduce manufacture period CTO and the deposition of cushion of photovoltaic device and move back The needs of the number of steps of fire, cause cost and the manufacturing capacity of raising reduced.Additionally, deposit Provide use have desired electrical and optical properties cadmium tin manufacture cost-effective Electrode and the needs of photovoltaic device.

Summary of the invention

Embodiments of the invention are provided to meet these and other needs.One embodiment side of being Method.The method is included on supporter the cadmium tin oxide layer arranging generally amorphous, and passes through The first surface of this amorphous oxide cadmium tin layers is exposed to electromagnetic radiation and by this amorphous oxide cadmium Tin layers rapid thermal annealing forms clear layer.

Another embodiment is the method making photovoltaic device.The method is included on supporter and sets Put the cadmium tin oxide layer of generally amorphous and by by the first table of this amorphous oxide cadmium tin layers Face is exposed to electromagnetic radiation and by this amorphous oxide cadmium tin layers rapid thermal annealing to form clear layer. The method further includes at and arranges the first semiconductor layer on this clear layer；At this first quasiconductor Second semiconductor layer is set on Ceng；And back contact is set on this second semiconductor layer and carrys out shape Become photovoltaic device.

Still further embodiment is method.The method is included on supporter and arranges generally amorphous Cadmium tin oxide layer and by the first surface of this amorphous oxide cadmium tin layers is exposed to electromagnetism Radiate and this amorphous oxide cadmium tin layers rapid thermal annealing is formed clear layer.This clear layer includes There is the cadmium tin of the most single-phase spinel-type (spinel) crystal structure, and have little In about 2x10^-4The resistivity of Ω-cm.

Accompanying drawing explanation

When following detailed description is read referring to the drawings, these and other features of the present invention, side Face and advantage will become better understood, wherein:

Fig. 1 be according to an exemplary embodiment of the invention be arranged on supporter the most non- The schematic diagram of brilliant cadmium tin oxide layer.

Fig. 2 is the schematic diagram of transparency electrode according to an exemplary embodiment of the invention.

Fig. 3 is the schematic diagram of transparency electrode according to an exemplary embodiment of the invention.

Fig. 4 is the schematic diagram of photovoltaic device according to an exemplary embodiment of the invention.

Fig. 5 is the schematic diagram of photovoltaic device according to an exemplary embodiment of the invention.

Fig. 6 is the schematic diagram of photovoltaic device according to an exemplary embodiment of the invention.

Fig. 7 is the schematic diagram of photovoltaic device according to an exemplary embodiment of the invention.

Fig. 8 is the schematic diagram of photovoltaic device according to an exemplary embodiment of the invention.

Fig. 9 A illustrates the digital picture of the cadmium tin oxide layer of unannealed generally amorphous.

Fig. 9 B illustrates the digital picture of clear layer according to an exemplary embodiment of the invention.

Figure 10 illustrates the optical transmittance curve of clear layer according to an exemplary embodiment of the invention.

Figure 11 illustrates the letter as lamp power of clear layer according to an exemplary embodiment of the invention The sheet resistance value of number.

Figure 12 illustrates the XRD style of clear layer according to an exemplary embodiment of the invention.

Figure 13 A illustrates the XPS profile of the cadmium tin oxide layer of the generally amorphous of deposited.

Figure 13 B illustrates the XPS profile of clear layer according to an exemplary embodiment of the invention.

Figure 14 is shown as the sheet resistance of the function that autotransformer (vasiac) is arranged.

Figure 15 is shown as the sheet resistance of the function of pulse width.

Figure 16 is shown as the sheet resistance of the function of lamp energy.

Figure 17 is shown in the digitized map of the generally cadmium tin oxide layer of amorphous after each annealing steps Picture.

Figure 18 illustrates the XRD style of clear layer according to an exemplary embodiment of the invention.

Figure 19 illustrates amorphous oxide cadmium stannum and the absorption curve of crystallization cadmium tin.

Detailed description of the invention

As discussed in detail below, some in embodiments of the invention provide a mean for quickly Thermal annealing forms the method for crystallization cadmium tin oxide layer.The method can use costliness by getting rid of CdS/ glass sacrificial section (typically using in closing on annealing) realizes being used for forming crystallization oxygen The cost-effective of cadmium stannum can manufacturing process.Additionally, the method allows to avoid at annealing process Period needs the continuous processing of manual intervention, and annealing time can cause higher life faster Production capacity power and lower manufacturing cost.This rapid thermal anneal process also allows for use to be had and is less than The relatively inexpensive supporter of the softening temperature of 600 DEG C, such as soda-lime glass etc..

Some in embodiments of the invention further provide for having gradual change Aska-Rid. for formation The transparency electrode of tin layers and the method for photovoltaic device.This gradual change cadmium tin oxide layer can be implemented at some Example advantageously rises the function of including transparent conducting oxide layer and cushion, or alternatively at some its His embodiment is easy to arrange crystallization buffer layer, thus realize crystallization that this cushion strengthens and Performance.This gradual change cadmium tin oxide layer thus can this photovoltaic device production period provide cost fall Low and by reducing optical absorption in Window layer, reducing total reflection and optimize this device Open-circuit voltage and the device performance that strengthens.

Approximating language as used the most in the specification and in the claims can be applicable to Modifying any quantificational expression, it can change permissibly and not cause its basic training associated therewith Change in energy.Therefore, the term such as such as " about " or multiple term the value modified does not limits Exact value in regulation.In some instances, this approximating language may correspond to for measuring this value The degree of accuracy of instrument.

In following specification and claims, singulative " " and " being somebody's turn to do " include multiple Several refer to thing, unless the context clearly dictates otherwise.

As used herein, term "available" and " can be " indicate: send out in one group of situation Raw probability；There is the character of regulation, characteristic or function；And/or by expressing and modification Ability, performance or the probability of verb association one or more modify this verb.Therefore, The term using instruction to be modified of "available" and " can be " can property, merit for indicate It is the most suitable, competent or suitable for or using, but considers in some cases should The term modified may not be suitable, competent or suitable.Such as, at some In the case of, it is contemplated that event or can property, and in other cases this event or can property not Can occur, this difference is correctly expressed by term "available" and " can be ".

Term " transparent region ", " clear layer " and " transparency electrode " refers to as used herein The region of average transmission, layer or the article of at least the 80% of permission incidence electromagnetic radiation, this electromagnetism Radiation has the wavelength in from about 300nm to the scope of about 850nm.As made herein , term " it is arranged on ... on " refer to that layer is directly arranged in contact with each other or by having in-between Interposed layer is had indirectly to be arranged in contact with each other.

As discussed in detail below, some embodiments of the present invention are for being used for forming transparency electrode The method of the crystallization cadmium tin oxide layer of the improvement with photovoltaic device.With reference to Fig. 1-8, the method is described. As indicated, the most in FIG, the method be included in arrange on supporter 110 the most non- Brilliant cadmium tin oxide layer 120.The cadmium tin oxide layer 120 of this generally amorphous includes first surface 122 and second surface 124.In one embodiment, this second surface 124 is adjacent to this Support body 110.

As used herein, term " cadmium tin " includes the composition of cadmium, stannum and oxygen.One In a little embodiments, cadmium tin includes the stoichiometric composition of cadmium and stannum, and the most such as cadmium is to stannum Atomic ratio be about 2: 1.In some other embodiments, cadmium tin includes cadmium and stannum Nonstoichiometric composition, the most such as cadmium are being less than about 2: 1 or more than big to the atomic ratio of stannum In the scope of about 2: 1.As used herein, term " cadmium tin " and " CTO " can be mutual Use with changing.In certain embodiments, cadmium tin can farther include one or more doping Agent, such as copper, zinc, calcium, yttrium, zirconium, hafnium, vanadium, stannum, ruthenium, magnesium, indium, zinc, palladium, Rhodium, titanium or its combination." the generally cadmium tin of amorphous " refers to do not have as used herein Just like the cadmium tin oxide layer substantially crystallizing style observed by X-ray diffraction (XRD).

In certain embodiments, cadmium tin can play the function of transparent conductive oxide (TCO). Cadmium tin has many advantages as TCO, and it includes working as and stannum oxide, Indium sesquioxide., oxygen Change have when indium stannum and other transparent conductive oxides compare preferable electricity, optics, surface and Engineering properties and the stability increased at elevated temperatures.These electrical property of cadmium tin Matter can depend in part on atomic concentration by cadmium and stannum in certain embodiments, or alternatively one By the group to the cadmium tin that the atomic ratio of stannum characterizes of the cadmium in cadmium tin in other embodiments a little Become.As used herein, cadmium refers to the cadmium atomic concentration to stannum in cadmium tin to the atomic ratio of stannum Ratio.The atomic concentration of cadmium and stannum and corresponding atomic ratio generally use such as X-ray photoelectricity Son spectrum (XPS) is measured.

In one embodiment, the cadmium atomic ratio to stannum in the CTO layer 120 of generally amorphous In the scope from about 1.2: 1 to about 3: 1.In another embodiment, generally amorphous CTO layer 120 in cadmium to the atomic ratio of stannum in the scope from about 1.5: 1 to about 2.5: 1 In.In still another embodiment of the invention, former to stannum of cadmium in the CTO layer 120 of generally amorphous Son ratio is in the scope from about 1.7: 1 to about 2.15: 1.In a particular embodiment, Generally in the CTO layer 120 of amorphous cadmium to the atomic ratio of stannum from about 1.4: 1 to about 2: 1 Scope in.

In one embodiment, in the CTO layer 120 of generally amorphous, the atomic concentration of cadmium exists From the scope of about 20% to about 40% of the total atom content of cadmium tin.At another In embodiment, generally in the CTO layer 120 of amorphous the atomic concentration of cadmium from cadmium tin Total atom content about 25% to about 35% scope in.In particular embodiments, greatly In cause in the CTO layer 120 of amorphous the atomic concentration of cadmium from the total atom content of cadmium tin About 28% to about 32% scope in.In one embodiment, generally amorphous In CTO layer 120 atomic concentration of stannum from about the 10% of the total atom content of cadmium tin to In the scope of about 30%.In another embodiment, the CTO layer 120 of generally amorphous The atomic concentration of middle stannum is from about the 15% to about 28% of the total atom content of cadmium tin In scope.In particular embodiments, in the CTO layer 120 of generally amorphous, the atom of stannum is dense Degree is in the scope from about 18% to about 24% of the total atom content of cadmium tin.One In individual embodiment, generally in the CTO layer 120 of amorphous the atomic concentration of oxygen from Aska-Rid. In the scope of about 30% to about 70% of the total atom content of stannum.In another embodiment, Generally in the CTO layer 120 of amorphous, the atomic concentration of oxygen is containing from the total atom of cadmium tin In the scope of about 40% to about 60% of amount.In particular embodiments, generally amorphous In CTO layer 120 atomic concentration of oxygen from about the 44% of the total atom content of cadmium tin to In the scope of about 50%.

In one embodiment, generally the CTO layer 120 of amorphous passes through such as to sputter, change Any applicable technology such as vapour deposition, spin coating, spraying or dip-coating of learning are arranged on supporter 110 On.In one embodiment, the CTO layer 120 of generally amorphous can be by by supporter 110 Immerse the solution of the product comprising cadmium and stannum obtained by cadmium compound and tin compound and Formed.

In particular embodiments, the CTO layer 120 of generally amorphous is arranged on by sputtering On support body 110.In one embodiment, generally the CTO layer 120 of amorphous can pass through to penetrate Frequently (RF) sputtering or direct current (DC) sputtering are arranged on supporter 110.An enforcement In example, the generally CTO layer 120 of amorphous can pass through reactive sputtering in the presence of oxygen It is arranged on supporter 110.

In certain embodiments, the CTO layer 120 of generally amorphous uses ceramic alumina cadmium stannum Target is arranged on supporter 110.In some other embodiments, the generally CTO of amorphous Layer 120 uses Aska-Rid. and stannum oxide target by cosputtering or by from including Aska-Rid. and oxidation The single target of the mixture of stannum sputters and is arranged on supporter 110.In some other embodiments In, the generally CTO layer 120 of amorphous uses single metal target (wherein this metallic target includes Cadmium and the mixture of tin metal) by reactive sputtering, or use two different metallic targets (i.e., Cadmium target and stannum target) it is arranged on supporter 110 by reaction cosputtering.Sputtering target can pass through Any technique and employing are suitable for and any suitable sputter tool, machine, equipment or system one Play any shape of use, form or configure and manufacture, formed or shape.

When by sputtering at the CTO layer 120 depositing generally amorphous on supporter 110, Cadmium in sedimentary just can become with the atomic concentration of cadmium in sputtering target and stannum with the atomic concentration of stannum Ratio.In one embodiment, in sputtering target cadmium to the atomic ratio of stannum from about 1.4: 1 to greatly In the scope of about 3: 1.In another embodiment, in sputtering target cadmium to the atomic ratio of stannum from In the scope of about 1.5: 1 to about 2.5: 1.In still another embodiment of the invention, cadmium in sputtering target To the atomic ratio of stannum in the scope from about 1.7: 1 to about 2.15: 1.The most real at one Execute in example, in sputtering target cadmium to the atomic ratio of stannum in the scope from about 1.4: 1 to about 2: 1.

In certain embodiments, generally the thickness of the CTO layer 120 of amorphous passes through arranging Change one or more in the processing parameter of employing during step and control.An embodiment In, generally the thickness of the CTO layer 120 of amorphous be designed to from about 50nm to about In the scope of 600nm.In another embodiment, the CTO layer 120 of generally amorphous Thickness has the thickness in from about 100nm to the scope of about 500nm.The most real Execute in example, generally the thickness of the CTO layer 120 of amorphous have from about 200nm to greatly Thickness in the scope of about 400nm.

As indicated, the most in FIG, supporter 110 farther includes first surface 112 With second surface 114.In one embodiment, solar radiation is incident on this first surface 112 On, and the CTO layer 120 of generally amorphous arranges this second surface 114 neighbouring.So Example in, the configuration of supporter 110 and CTO layer 120 also referred to as " top board " configuration. In one embodiment, supporter 110 is at the wavelength for being expected that by supporter 110 transmission It is transparent in scope.In one embodiment, supporter 110 can be for having from about The visible ray of the wavelength in the scope of 400nm to about 1000nm is transparent.Yet another In individual embodiment, the thermal coefficient of expansion of supporter 110 is close to the CTO layer 120 of generally amorphous Thermal coefficient of expansion, prevent the CTO layer 120 of generally amorphous from during heating treatment ftractureing Or bending.In certain embodiments, some other layer may be provided at the CTO of generally amorphous Between layer 120 and supporter 110, such as reflecting layer etc..

In certain embodiments, supporter 110 includes being resistant to the heat more than about 600 DEG C The material for the treatment of temperature, such as Silicon stone and borosilicate glass etc..In some other embodiments, Supporter 110 includes the material with the softening temperature less than 600 DEG C, such as soda-lime glass etc.. Typically, using the supporters such as such as soda-lime glass is impossible for the annealing of CTO, Because the annealing temperature used is more than 600 DEG C, it is more than the softening temperature of soda-lime glass.Thus, Use the supporters such as such as soda-lime glass for wherein using the temperature more than 600 DEG C for annealing The production of photovoltaic device be infeasible.In certain embodiments, the Rapid Thermal of the present invention is moved back Fire step causes the fast temperature of supporter-amorphous CTO assembly to increase, and avoids supporter It is continuously exposed to the time period that the constant temperature more than 600 DEG C extends.Not by any special reason In the case of opinion constraint, it is believed that due to by the bigger energy absorption of amorphous CTO layer, Rapid Thermal Annealing steps much more quickly heats amorphous CTO layer than supporter.Therefore, implement at some In example, rapid thermal anneal step can allow amorphous CTO layer to be heated to the temperature more than supporter Degree, thus supporter is not softened by the annealing of CTO layer.In certain embodiments, the party Method advantageouslys allow for using low softening temperature (less than the 600 DEG C) supporters such as such as soda-lime glass For forming photovoltaic device.

In some other embodiments, as illustrated the most in fig. 2, the generally CTO of amorphous Layer 120 is arranged on supporter 110 so that solar radiation is incident on the first surface of clear layer On 131 and the second surface 133 of clear layer arranges the second surface of neighbouring supporter 110 114.In such example, the configuration of supporter 110 and CTO layer 120 also referred to as " lining The end " configuration.Supporter 110 includes that such as the stacking of the multilamellar illustrated in figure 6, the such as back of the body connect Contact layer 160 is arranged on back support body 190, and the second semiconductor layer 150 is arranged on this back contacts On layer 160, and the first semiconductor layer 140 is arranged on this second semiconductor layer 150.? In such embodiment, the generally CTO layer 120 of amorphous is arranged on this first semiconductor layer On 140.

As indicated, the most in FIG, the method farther includes the CTO of generally amorphous The first surface 122 of layer is exposed to electromagnetic radiation 100.As indicated, the most in fig. 2, The method includes in addition by transparent to be formed for CTO layer 120 rapid thermal annealing of generally amorphous Layer 130.In certain embodiments, the clear layer 130 being arranged on supporter 110 is formed Prescribed electrode 200.

Term " rapid thermal annealing " refers to more than about 200W/cm as used herein²'s The surface of the CTO layer 120 of the incident power densities irradiation generally amorphous in scope is formed The CTO layer generally crystallized.Term " incident power densities " refers to greatly as used herein The power that in cause, on the first surface 122 of the CTO layer 120 of amorphous, per unit surface area is incident. In certain embodiments, rapid thermal annealing farther includes so that the CTO of generally amorphous The rate of heat addition that layer the is subject to incident power densities irradiation generally amorphous more than about 20 DEG C/sec The surface of CTO layer 120.Term " rate of heat addition " refers to amorphous CTO as used herein Layer carries out the Mean Speed heating to reach desired annealing temperature.In certain embodiments, soon Speed thermal annealing is included such that the rate of heat addition that the CTO layer of generally amorphous is subject to is more than about The surface of the CTO layer 120 of the incident power densities irradiation generally amorphous of 100 DEG C/sec.One In other embodiments a little, rapid thermal annealing farther includes so that in order to reach desired annealing The time that temperature is spent is big less than the incident power densities of about 60 seconds and rate of heat addition irradiation The surface of the CTO layer 120 of amorphous in cause.

As used herein term " electromagnetic radiation " refers to have electrically and magnetically both fields and passing with ripple The radiation broadcast.Electromagnetic radiation can by wavelength be categorized into radio, microwave, infrared, visibility region, Ultraviolet, X-ray and gamma ray.In one embodiment, the CTO layer of generally amorphous The rapid thermal annealing of 120 includes the CTO layer 120 of generally amorphous is exposed to high-strength magnetic Radiation makes to realize the controlled annealing of the CTO layer 120 of generally amorphous.An embodiment In, the generally rapid thermal annealing of the CTO layer 120 of amorphous includes the CTO of generally amorphous Layer 120 is exposed to high-intensity red external radiation 100 and the CTO layer 120 of generally amorphous is inhaled Receive the optical photon (light photon) of significant part." infra-red radiation " includes having greatly The electromagnetic wave of the wavelength in the scope of about 700nm.

In one embodiment, the rapid thermal annealing of the generally CTO layer 120 of amorphous includes The CTO layer 120 of generally amorphous is exposed to intensity-wave spectrum high-strength with restriction Degree electromagnetic radiation makes the CTO layer 120 of generally amorphous absorb the optical photon of significant part. Figure 19 illustrates unannealed amorphous CTO and the crystallization CTO function as electromagnetic radiation wavelength Absorption curve.As illustrated in Figure 19, the absorption profile of crystallization CTO layer is different from amorphous The absorption profile of CTO layer.Therefore, in certain embodiments, amorphous and the light of crystallization CTO Learn character to be advantageously used for using controlled manner to provide rapid thermal annealing.

As illustrated in the diagram, amorphous is unannealed CTO is for having the ripple less than 300nm Long photon has the highest optical absorption (more than 90%).Similarly, crystallization CTO Generally there is identical optical absorption (it is more than for having the photon of the wavelength less than 300nm 30%).In one embodiment, the generally CTO layer 120 of amorphous is exposed to and has little The electromagnetic radiation of the wavelength in the scope of about 300nm.In such example, electromagnetism spoke Penetrate and the radiation with the wavelength more than about 300nm can be made from incident radiation through light filter Remove.The a large amount of photons absorbed by amorphous CTO layer in this wave-length coverage can cause temperature in film The rapid increase of degree, causes the change from amorphous to crystal form very fast.The most any In the case of theoretical constraint, it is believed that by using the ripple in the scope less than about 300nm Long, the CTO layer of generally amorphous the amount of the incident power densities absorbed with by generally tying The power density that brilliant CTO layer absorbs is substantially the same.Therefore, in such example, The CTO layer generally phase of the rate of heat addition of the CTO layer generally crystallized and generally amorphous With, thus reduce the probability making crystallization CTO layer overheated.Because the light of CTO layer after Tui Huo Learn the change in character and may not affect the power absorbed by this layer, the wavelength less than 300nm Use thus the more stable annealing of amorphous CTO layer can be allowed.In certain embodiments, should Method includes being exposed to the first surface 122 of the CTO layer 120 of generally amorphous have Ultraviolet radiation 100 less than the wavelength in the scope of about 300nm.Term is " in scope Wavelength " refer to the electromagnetic radiation with the spectrum of wavelength in this range, and it is not limited to single Wavelength or monochromatic radiation.

In another embodiment, the electromagnetic radiation used for rapid thermal annealing has and is being less than Wavelength in the scope of about 600nm.As illustrated in Figure 19, the absorption of crystallization CTO Fall considerable shown in profile absorption between the wave-length coverage of about 350nm to 600nm Low.Therefore, in such example, crystallization CTO layer the incident power densities absorbed Amount is less than the power density absorbed by the CTO layer of generally amorphous.Therefore, in such reality Executing in example, the rate of heat addition of the CTO layer generally crystallized can be less than the CTO of generally amorphous Layer, thus reduce the probability making crystallization CTO layer overheated.

In still another embodiment of the invention, for rapid thermal annealing use electromagnetic radiation have from Wavelength in the scope of about 450nm to about 600nm.It is not bound by any theory In the case of, it is believed that when the CTO layer 120 of generally amorphous become crystallization time because crystallization CTO is substantially transparent for the electromagnetic radiation in the wave-length coverage of 450nm to 600nm , therefore optical absorption reduces, as illustrated in Figure 19.Reduce when CTO crystallizes Optical absorption may result in the significantly reduced heating that crystallization CTO layer causes due to electromagnetic radiation. Therefore, in such example, rapid thermal anneal process can substantially play " from limiting " technique Function, the behavior i.e. crystallized prevent CTO layer overheat to damage this layer point.For The wave-length coverage of the selection that rapid thermal annealing uses can depend in part on the optics of amorphous CTO layer The photon spectrum of the electromagnetic radiation of characteristic, the optical property of crystallization CTO layer and use.

In certain embodiments, the rapid thermal annealing of the generally CTO layer 120 of amorphous includes First surface 122 is exposed to the electromagnetic radiation that never coherent source is launched.As used herein Term " light " refers to electromagnetic radiation defined as above.Term " incoherent light as used herein Source " assign the light wave being set to launch different wave length or there is phase co-wavelength but mutually different phase place The light source of the light wave of (situation of synchronous coherent light mutual with wherein light wave is contrary).Such as this The term " irrelevant light source " that literary composition uses refers to single source or multiple light source further.

In one embodiment, irrelevant light source has expected range from being configured to launch The light of wavelength or any applicable light source of electromagnetic radiation select.In certain embodiments, Irrelevant light source is from the group being made up of Halogen light, uviol lamp, high-intensity discharge lamp and its combination Middle selection.In particular embodiments, irrelevant light source includes the array of Halogen light or Halogen light.

In certain embodiments, irrelevant light source can be further configured to use pulse mode to launch Electromagnetic radiation.In certain embodiments, the pulse width that irrelevant light source can be fixed launches electricity Magnetic radiation.Term " pulse width " refers to that amorphous CTO layer is exposed to electromagnetism as used herein Radiate 100 durations.

Irrelevant light source can be partly characterized in that incident power densities, lamp power or pulse width In one or more.In one embodiment, irrelevant light source can have from about 100w/cm²To about 500w/cm²Scope in incident power densities.The most real at one Executing in example, irrelevant light source can have from about 200w/cm²To about 400w/cm²Model Incident power densities in enclosing.

In one embodiment, irrelevant light source can be characterised by from about 1.4kW to about Lamp power in the scope of 2kW.In a particular embodiment, irrelevant light source can feature exist Lamp power in the scope of Yu Cong about 1.4kW to about 1.8kW.As mentioned above, Rapid thermal anneal step can include having power 1.4kW to about 1.8kW in certain embodiments Single lamp, or multiple lamp can be included in some other embodiments, each have from greatly Power in the scope of about 1.4kW to about 1.8kW.

In certain embodiments, generally the CTO layer 120 of amorphous first surface 122 with Fixed pulse width is exposed to irrelevant light source.In some other embodiments, generally amorphous The first surface 122 of CT0 layer 120 be exposed to the irrelevant light source with variable pulse width. In one embodiment, the generally CTO layer 120 of amorphous is exposed to electromagnetic radiation 100 and holds Continue in the time from the scope of about 1 second to about 120 second.In another embodiment, Generally the CTO layer 120 of amorphous be exposed to electromagnetic radiation 100 continue from about 5 seconds to Time in the scope of about 80 seconds.In particular embodiments, the CTO layer of generally amorphous 120 are exposed to electromagnetic radiation 100 continues from the scope of about 10 seconds to about 40 seconds Time.

In certain embodiments, rapid thermal anneal step can repeat n time further, and wherein n is In the scope from the scope of 2 to 20.In particular embodiments, rapid thermal anneal step can Repeat 2-8 time.For involving the embodiment of the repetition of thermal anneal step, pulse width can be to often Individual thermal anneal step is identical, can be maybe different to different annealing steps.Thermal annealing walks Rapid number or pulse width can depend in part on the thickness of supporter 110, generally amorphous Thickness or the incident power densities of CTO layer 120 and change.

Electromagnetic radiation is absorbed by the CTO layer 120 of generally amorphous and is converted into and causes this layer Temperature be increased rapidly to the heat energy for the treatment of temperature.In the case of not being bound by theory, it is believed that In this layer, quickly increasing of temperature causes from the CTO of generally amorphous to generally crystallizing The change of CTO.The percentage ratio conversion of the generally CTO of amorphous to the CTO generally crystallized The amount of the incident power densities absorbed by the CTO layer 120 of generally amorphous can be depended in part on With the thermal losses from this layer 120.In one embodiment, the CTO layer 120 of generally amorphous At least absorb percent the 80 of incident power densities.In another embodiment, generally amorphous CTO layer 120 at least absorb percent the 50 of incident power densities.In particular embodiments, The generally CTO layer 120 of amorphous at least absorbs percent the 10 of incident power densities.As relatively Early mention, in certain embodiments, the CTO layer 120 of generally amorphous the merit absorbed The amount of rate density can part be controlled advantageous by the energy wave spectrum of tuning electromagnetic radiation 100 System.In such example, by controlling the power absorbed by the CTO layer of generally amorphous The amount of density, can control in the rate of heat addition or treatment temperature is one or more.

In one embodiment, the CTO layer 120 of generally amorphous is with from about 700 DEG C Treatment temperature heating to the scopes of about 1200 DEG C.In another embodiment, substantially The CTO layer of upper amorphous is with in the process temperature from the scope of about 700 DEG C to about 900 DEG C Degree heating.In particular embodiments, the CTO layer of generally amorphous is with from about 800 DEG C Treatment temperature heating to the scopes of about 900 DEG C.Treatment temperature as used refers to generally The CTO layer of amorphous be exposed to electromagnetic radiation continue for rapid thermal anneal step enough time Temperature after between.

Rapid thermal anneal process is further by changing the pressure used during rapid thermal annealing Condition and control.In one embodiment, rapid thermal annealing is carried out under vacuum, vacuum Condition is defined herein as the pressure condition less than atmospheric pressure.In certain embodiments, quickly Thermal annealing can be carried out with constant pressure in the presence of argon.In some other embodiments In, rapid thermal annealing can be carried out under dynamic pressure by continuous sucking.In one embodiment, Rapid thermal annealing is real with the pressure equal to or less than about 700 torr in the presence of argon OK.In another embodiment, rapid thermal annealing in the presence of argon with equal to or little Pressure in about 500 torr is carried out.In still another embodiment of the invention, rapid thermal annealing is at argon In the presence of with equal to or less than about 250 torr pressure carry out.

As mentioned above, the rapid thermal annealing of the generally CTO layer 120 of amorphous causes The formation of bright layer 130.In one embodiment, this clear layer 130 includes the most uniform Single-phase polycrystalline CTO, it is such as formed by being annealed by the CTO layer 120 of generally amorphous. In certain embodiments, the cadmium tin generally crystallized has inverse spinel type crystal structure. This generally uniform single phase crystalline CTO forming this clear layer 130 is referred to herein as " oxygen Cadmium stannum ", as be arranged on supporter 110 and be heat treated to form this clear layer 130 " the generally CTO of amorphous " layer 120 have any different.In certain embodiments, this clear layer Can have desired electrical and optical properties, and transparent conductive oxide (TCO) layer can be played Function.In certain embodiments, this clear layer 130 can farther include amorphous component, example Such as amorphous oxide cadmium, amorphous oxide stannum or its combination etc..

Can be further characterized by thickness, electrical properties or optical property one of clear layer or Multiple.In one embodiment, clear layer 130 has from about 100nm to about 600nm Scope in thickness.In another embodiment, clear layer 130 has from about 150nm Thickness to the scope of about 450nm.In particular embodiments, clear layer 130 has From about 100nm to the scope of about 400nm thickness.In certain embodiments, thoroughly Bright layer 130 has less than about 4x10^-4The average resistivity (ρ) of Ω-cm.At some other In embodiment, clear layer 130 has less than about 2x10^-4The average resistivity (ρ) of Ω-cm. In certain embodiments, clear layer 130 has the average optical absorbance more than about 80%. In some other embodiments, clear layer 130 has the average optical transmission more than about 95% Rate.

As mentioned earlier herein, rapid thermal anneal step be not conventionally used for cadmium tin Carry out in the case of the CdS film of annealing or the external source of cadmium.Therefore, the Rapid Thermal of the present invention is moved back Fire step eliminates can not prepared with supporter (it is later used to the annealing of cadmium tin) is upper again " sacrifice " additional step of CdS film (by adjacent to cadmium tin oxide layer or being just close to by CdS film The cadmium tin oxide layer of annealing is placed).Additionally, rapid thermal anneal step also reduces at photovoltaic device Production in the amount of CdS that uses, and be economically advantageous, because CdS is expensive Material.The method also allows for (moving back typically for CTO and CdS layer with minimum of interference Assembling before and after ignition technique and disassemble required intervention) form the continuous of CTO layer Technique.Therefore, rapid thermal anneal process also results in the process of the reduction causing more high productive capacity Time, it can cause lower manufacturing cost.

In one embodiment, the clear layer 130 as indicated the most in fig. 2 includes across this layer The cadmium tin concentration of the generally homogenizing of the thickness of 130.In such example, across transparent Cadmium and the atomic concentration of stannum in this clear layer of the thickness of layer are the most constant.As herein Term " the most constant " meaning used is cadmium and the stannum of the thickness across clear layer 130 Change in atomic concentration is less than about 10%.

In another embodiment, the clear layer as indicated the most in figure 3 includes first area 132 and second area 134.This first area 132 includes cadmium tin, and this secondth district Territory 134 includes stannum and oxygen.In certain embodiments, this second area 134 farther includes cadmium, And the atomic concentration that cadmium is in this second area 134 is less than cadmium in this first area 132 Atomic concentration.Therefore, in such example, generally the CTO layer 120 of amorphous is fast Speed thermal annealing causes the shape in this second area 134 with the clear layer 130 of cadmium depletion region Become.

In one embodiment, first area 132 includes having the most single-phase spinel-type crystalline substance The cadmium tin of body structure.As mentioned about clear layer 130 earlier herein, clear layer 130 Interior first area 132 plays the function of tco layer in certain embodiments.First area 132 Electrical properties can depend in part on the composition of cadmium tin, its in certain embodiments by cadmium and The atomic concentration of stannum, or alternatively in some other embodiments by cadmium tin in cadmium to stannum Atomic ratio characterizes.Therefore, in certain embodiments, it may be advantageous in design first area 132 Cadmium provides desired electrical properties to the atomic ratio of stannum.

In one embodiment, in first area 132 cadmium to the atomic ratio of stannum from about 1.2: 1 In scope to about 3: 1.In another embodiment, in first area 132 cadmium to stannum Atomic ratio is in the scope from about 1.5: 1 to about 2.5: 1.In still another embodiment of the invention, In first area 132 cadmium to the atomic ratio of stannum in the scope from about 1.7: 1 to about 2.15: 1 In.In a particular embodiment, in first area 132 cadmium to the atomic ratio of stannum from about In the scope of 1.4: 1 to about 2: 1.

In one embodiment, in first area 132 cadmium to the atomic ratio of stannum across first area 132 Thickness be the most constant.Term " the most constant " meaning is as used herein Cadmium is less than about 10% to the thickness across first area 132 that changes in the atomic ratio of stannum.One In individual embodiment, first area 132 have from about 100nm to the model of about 500nm Thickness in enclosing.In another embodiment, first area 132 has from about 150nm Thickness to the scope of about 450nm.In particular embodiments, first area 132 has Thickness in from about 100nm to the scope of about 400nm.In certain embodiments, The more high conductivity of first area 132 can supply optical transmittance.First area 132 higher Electrical conductivity or more low-resistivity can allow thinner first area, and it increases optical transmission further Rate.

Clear layer 130 farther includes the Rapid Thermal of the CTO layer 120 by generally amorphous The second area 134 that annealing is formed, it includes stannum and oxygen.In certain embodiments, this second Region 134 by cadmium with non-from cadmium tin of the treatment conditions that use during rapid thermal annealing Stoichiometry distillation is formed.In the case of not being bound by theory, it is believed that at amorphous CTO layer Above in the of 120, the steam pressure of cadmium is higher than the steam pressure of stannum, causes during heating treatment on surface Cadmium exhaust.In certain embodiments, cadmium exhaust from surface controlled cause having controllable thickness, The formation of the second area 134 of form and composition.

In certain embodiments, second area 134 can have the resistance more than first area 132 The resistivity of rate.In certain embodiments, the function of tco layer can be played in first area 132, And second area can play the function of cushion.Thus, in certain embodiments, the method bag The composition including advantageously design clear layer 130 makes clear layer 130 to change across the thickness of this layer Not only play tco layer but also play the function of cushion.In some other embodiments, second area 134 Crystallization buffer (such as, stannum oxide) layer forming core on clear layer 130 of individually deposition can be assisted, Cause higher-quality cushion.

As above with reference to described in first area 132, the electrical properties of second area 134 also may be used Depend in part on the cadmium concentration to stannum in the composition of second area 134 or second area 134.? In some embodiments, second area 134 includes stannum oxide.In certain embodiments, the secondth district Territory 134 farther includes cadmium.In one embodiment, cadmium atom in second area 134 Concentration is less than about 20%.In another embodiment, cadmium atom in second area 134 Concentration is less than about 10%.In particular embodiments, cadmium atom in second area 134 is dense Degree is less than about 0.5%.

In some other embodiments, second area 134 is substantially free from cadmium.As used herein Be cadmium atomic concentration in second area 134 less than about substantially free from the cadmium meaning 0.01%.In one embodiment, cadmium atomic concentration in second area 134 is less than about 0.001%.In one embodiment, cadmium atomic concentration in second area 134 is about 0%.

In certain embodiments, in second area 134 cadmium to the atomic ratio of stannum across second area 134 Thickness be the most constant.As earlier mentioned, term as used herein is " generally Constant " meaning is that the change in the atomic ratio of stannum is less than by cadmium across the thickness of second area 134 About 10%.In certain embodiments, the thickness of second area 134 is by changing in Rapid Thermal During annealing process use treatment temperature, persistent period and vacuum condition in one or more Control.In one embodiment, the thickness of second area 134 is designed to from about 10hm To the scope of about 300nm.In another embodiment, second area 134 have from Thickness in the scope of about 50nm to about 250nm.In particular embodiments, the secondth district Territory 134 has the thickness in from about 20nm to the scope of about 200nm.

As indicated, the most in the diagram, clear layer 130 wraps the most further Include the transition region 136 inserted between first area 132 and second area 134.This transition zone Territory 136 includes that the atomic ratio to stannum of cadmium in cadmium, stannum and oxygen, and this transition region 136 is across this The thickness of transition region 136 changes.In a particular embodiment, in this transition region 136 The atomic ratio of stannum is reduced to second area 134 by cadmium from first area 132.

In certain embodiments, transition region 136 includes the continuous ladder of atomic concentration of cadmium and stannum Degree.In transition region 136, this continuous gradient of the atomic concentration of cadmium and stannum allows first area 132 The function of transparent conductive oxide (TCO) layer (rise) and second area be 134 (cushion Function) between the continuous transformation of composition.Thus, the gradual change cadmium tin (CTO) of the present invention Layer generally eliminates the device junction produced by first depositing tco layer followed by cushion Non-continuous face between tco layer and cushion specific to structure.In thin-film solar cells The existence of the non-continuous face between functional layer may result in optical loss, electrical losses or adhesive force One or more in variability.

In certain embodiments, the thickness of transition region 136 is by changing in rapid thermal annealing work One or more controls in the treatment temperature, persistent period and the vacuum condition that use during skill. In one embodiment, the thickness of transition region 136 be designed to from about 10nm to about In the scope of 200nm.In another embodiment, transition region 136 has from about Thickness in the scope of 20nm to about 150nm.In particular embodiments, transition region 136 There is the thickness in from about 40nm to the scope of about 100nm.

First area 132 and second area 134 can be further characterized by their electricity and light Learn character.In certain embodiments, second area 134 has is the resistance of first area 132 The resistivity that rate is 1000 times.In some other embodiments, it is that second area 134 has The resistivity of the resistivity in one region 132 100 times.In certain embodiments, second area 134 There is the resistivity of the resistivity 50 times being first area 132.

In certain embodiments, first area 132 has less than about 4x10^-4Ω-cm's is average Resistivity (ρ).In some other embodiments, first area 132 has less than about 2x10^-4The average resistivity (ρ) of Ω-cm.In certain embodiments, second area 134 has Have more than about 10^-3The average resistivity (ρ) of Ω-cm.In certain embodiments, the secondth district Territory 134 has more than about 10^-2The average resistivity (ρ) of Ω-cm.First area 132 He Second area 134 has the average optical absorbance more than about 80% further.Real at some Executing in example, the transparency electrode 200 as such as indicated in Fig. 2-4 has more than about 80% Average optical absorbance.In some other embodiments, transparency electrode 200 has more than about The average optical absorbance of 95%.

As discussed in detail below, some embodiments of the present invention are further directed to for making light The method of volt device.With reference to Fig. 1-8, the method is described.As indicated, the most in FIG, The method is included in the CTO layer 120 arranging generally amorphous on supporter 110.This is generally The CTO layer 120 of amorphous includes first surface 122 and second surface 124.Additionally, as such as Indicating in FIG, the method includes exposing the first surface 122 of amorphous oxide cadmium tin layers In electromagnetic radiation 100.The method farther includes quick for the CTO layer 120 of generally amorphous Thermal annealing forms clear layer 130, as indicated in fig. 2.In certain embodiments, if The clear layer 130 put on supporter 110 forms transparency electrode 200.As the most in Figure 5 Instruction, the method further includes at and arranges the first semiconductor layer 140 on clear layer 130； This first semiconductor layer 140 arranges the second semiconductor layer 150；And the second half lead at this Back contact 160 is set on body layer 150 to form photovoltaic device 300.As mentioned earlier herein , this rapid thermal anneal step avoids the need for the CTO at the generally amorphous using CdS film Conventional annealing during use one or more Additional manufacturing steps.As shown in fig. 5 Configuration is typically called " top board " configuration, and wherein solar radiation 400 is incident on supporter 110 On.Therefore, in such an arrangement, supporter 110 is substantially transparent, and this is desirable 's.

In one embodiment, it is provided that use the method that " substrate " configuration makes photovoltaic device. The method is included on supporter 110 clear layer 130 formed as described earlier so that the sun Radiation 400 is incident on clear layer 130, as shown in fig. 6.In such embodiment In, this supporter 110 includes the back contact 160 being arranged on back support body 190, second Semiconductor layer 150 is arranged on this back contact 160, and the first semiconductor layer 140 is arranged on this On second semiconductor layer 150, and clear layer 130 is arranged on this first semiconductor layer 140. In such an arrangement, because solar radiation is incident on clear layer 130, this back support body can Including metal.In some other embodiments, photovoltaic device can farther include to be arranged on such as One or more layers on the clear layers such as protective layer (not shown).In such example, Solar radiation can be incident on this protective layer and the most directly on clear layer 130.

The quick thermal annealing method of the present invention can advantageously allow for using and use " substrate " to configure CTO layer produces photovoltaic device.Not by the case of any theoretical especially constraint, it is believed that due to The absorption that amorphous CTO layer is bigger, rapid thermal anneal step than semiconductor layer (such as CdS, CdTe etc.) much more quickly heat amorphous CTO layer.Therefore, in certain embodiments, quickly Thermal anneal step can allow amorphous CTO layer to be heated to the temperature more than semiconductor layer, thus The annealing of CTO layer is not changed the character of semiconductor layer.

In certain embodiments, the first semiconductor layer 140 and the second semiconductor layer 150 can adulterate There are p-type dopant or n-type dopant to form hetero-junctions.As used in this context, Hetero-junctions is semiconductor junction, and it is made up of the layer with dissimilar semi-conducting material.These materials It is generally of unequal band gap.As example, hetero-junctions can pass through a conductivity-type Layer or region and layer or the region of opposite conductivities between contact formation, such as " p-n " knot.

In certain embodiments, the second semiconductor layer 150 includes absorbed layer.This absorbed layer is light A part for volt device, the electromagnetic energy of incident illumination (such as, daylight) is to electron hole pair (i.e., To electric current) conversion occur wherein.Light-sensitive material is typically employed to form this absorbed layer.Suitable The light-sensitive material closed includes cadmium telluride (CdTe), cadmium zinc telluride (CdZnTe), cadmium telluride Magnesium (CdMgTe), cadmium manganese telluride (CdMnTe), cadmium telluride sulfur (CdSTe), telluride Zinc (ZnTe), CuInS2 (copper, indium, sulfur), CIS (copper, indium, selenium), CIGS (copper, Indium, gallium, selenium), CIGSS (copper, indium, gallium, selenium, sulfur), iron sulfide (FeS₂) and Its combination.Light-sensitive semiconductor material mentioned above can alone or be applied in combination.Additionally, this A little materials can exist in more than one layer, and every layer has different types of light-sensitive material or has point The combination of the material in the layer opened.In a particular embodiment, the second semiconductor layer 150 wraps Include cadmium telluride (CdTe) as absorbing material.CdTe uses in film photovoltaic device Efficiently light-sensitive material.CdTe is relatively easy to deposit and it is taken as that is suitable for large-scale production. In one embodiment, the second semiconductor layer 150 has from about 1500nm to about Thickness in 4000nm scope.

First semiconductor layer 140 arranges neighbouring clear layer 130.In a particular embodiment, first Semiconductor layer 140 includes cadmium sulfide (CdS) and can be described as " Window layer ".A reality Executing in example, the first semiconductor layer 140 has from about 30nm to about 150nm scope Thickness.Back contact 160 arrange further neighbouring second semiconductor layer 150 and with its ohm Contact.Back contact 160 can include metal, quasiconductor or its combination.In some embodiments In, back contact 160 can include gold, platinum, molybdenum or nickel or zinc telluridse.In certain embodiments, One or more extra plays can be between the second semiconductor layer 150 and back contact 160, example Such as p+ type semiconductor layer.In certain embodiments, the second semiconductor layer 150 can include p-type tellurium Cadmium (CdTe), it can process further or adulterate to reduce back contacts resistance, such as, pass through Caddy (Cleary) processes or by forming zinc telluridse or telluride layers of copper on the back side.An embodiment In, back contacts resistance can be improved by the p-type carrier that increases in CdTe material with P+ type layer is formed on the back side of the CdTe material of back contact contact.

In certain embodiments, method farther include to be arranged on cushion 170 clear layer and Between first semiconductor layer 140, as indicated, the most in figure 6.In one embodiment, Cushion 170 includes from by stannum oxide, Indium sesquioxide., zinc oxide, zinc and its combination structure The oxide of the group selection become.In a particular embodiment, cushion 170 include stannum oxide or its Ternary mixed oxide.

Described above, in certain embodiments, rapid thermal anneal step causes at clear layer First area 132, second area 134 and transition region 136 is formed in 130.In such reality In example, as indicated, the most in the figure 7, the first semiconductor layer or Window layer 140 are adjacent to being somebody's turn to do Second area 134 is set directly on clear layer 130 and need not deposit Additional buffer layer Intermediate steps.In such embodiments, this second area 134 can be at the second semiconductor layer 150 Cushion or exhausted is played between (such as, CdTe) and first area 132 (function of a TCO) The function of edge layer.Additionally, second area 134 also can alleviate first area 132 (TCO's Function) and the first semiconductor layer 140 (such as, CdS) between interface stress and Thus lower stress level is formed at CdS/CdTe interface, and this interface defect contributes to Reduce the V of these devices_OC.Therefore, in certain embodiments, second in clear layer 130 Region 134 can need not Additional buffer layer is arranged on CTO layer and the first semiconductor layer 140 Between (such as, CdS).

In some other embodiments, Additional buffer layer 170 is neighbouring after rapid anneal step Second area 134 is arranged on clear layer 130, as indicated, the most in fig. 8.At this In the embodiment of sample, the first semiconductor layer 140 is arranged on cushion 170 and cushion 170 Arranging territory, adjacent second zone 134 makes second area 134 be easy at cadmium tin (CTO) layer On higher-quality cushion 170 is set and reduces cadmium tin (CTO) layer 132 further And the impact of the non-continuous face between cushion 170.

First semiconductor layer the 140, second semiconductor layer 150, back contact 160 or cushion One or more by the one or more depositions in following technology in 170 (optional): Sputtering, electro-deposition, silk screen printing, spraying, physical vapour deposition (PVD) or closing Space Sublimation.This One or more in a little layers can heat or with post processing further to manufacture photovoltaic device 300.

Example

Example below is provided to further illustrate certain embodiments of the present invention.These examples should not This reading limits the present invention in any way for adopting.

The CTO layer that example 1 rapid thermal annealing is arranged on borosilicate glass

The sputtering pressure using ceramic target and 16.5 millitorrs sputters at borosilicate by room temperature DC Cadmium tin (CTO) thin film is prepared in glass support.This borosilicate glass supporter has There is the thickness of about 1.3mm.Rapid thermal annealing (RTA) technique is in argon atmospher (～700 torr) Middle implementation and do not use the additional source of cadmium (to damage from the Cd of film during thermal annealing to compensate Consumption).Some 0.5 inch of x1 inch samples cut from 6 inches of x6 inch plates, cause boron On silicate glass～the amorphous CTO film of 216nm thickness.These samples are placed in the close of full argon Sealing in quartz ampoule and introduce the short annealing system of custom design, it is based on single 2 kilowatts of halogen Element lamp.This Halogen light is pulse and uses 30 seconds fixed pulse width.Change the merit of lamp Rate is explored and wherein the region of conversion will be occurred to need.Depend on that system is arranged, at some examples In, the sample peak temperature of estimation～900 DEG C near, wherein from the pact of incident radiation 30W/cm²Absorbed by sample.

Fig. 9 a and 9b catches rapid thermal annealing (RTA) visually to being arranged on borosilicate The impact of the CTO layer in glass support.Fig. 9 a illustrates the digitized map of CTO film before annealing As and Fig. 9 b the digital picture of CTO film after annealing is shown.Naked eyes are clearly visible due to single The transparency that RTA circulation causes improves.Figure 10 is shown with two sample (samples of RTA annealing Product 1 and 2) optical transmittance, its to for use CdS close on annealing process, similar Condition deposition and～the transparent curve of CTO films of 630 DEG C of annealing compare.Qualitatively, The transmittance graph obtained with RTA and acquisition after closing on annealing process that is closely similar.

4 point probes are used to measure the sheet resistance of CTO film before and after RTA.At RTA Before, the sheet resistance of film is the highest and can not measure.Figure 11 is shown in after RTA CTO The sheet resistance as Halogen light input power function that film is measured.The result of RTA test illustrates ～1.5 kw of power obtain～the minimum sheet resistance of 7ohms/square and exist relatively wide The power (1.42-1.55 kilowatt) of scope, for this relatively broad range of power kept thin Layer resistance closely minima (～7ohms/square).Along with power increases, sheet resistance Persistently rise beyond minimum point.

Figure 12 illustrates x-ray diffraction (XRD) flower for unannealed and RTA annealing specimen Sample.As seen in Figure 12, the amorphous CTO film for deposited does not observe XRD Style.By contrast, CTO film after the rta step is observed corresponding to oxidation The obvious peak of the crystallization cubic spinel type phase of cadmium stannum.In some samples, also at 2 θ～30 Little peak detected at degree, show the existence of stannum oxide.

Figure 13 a illustrates that the x-ray photoelectron spectroscopy of the CTO film of the generally amorphous of deposited is surveyed Amount (XPS) profile, its diagram cadmium is uniform to the thickness of the atomic ratio cross-film of stannum.Figure 13 b It is shown in the XPS profile of CTO film after experience RTA.Figure 13 b is shown in after stepping back, CTO film illustrates the concentration distribution that at least two is different: (a) illustrates for more than about 400 Etching period in second scope the most constant cadmium first area to the atomic ratio of stannum, and B () is for the cadmium depleted region of the etching period in 0 second to about 400 second scope.As Diagram in Figure 13 b, this first area has (schemes with for deposited amorphous oxide cadmium stannum film The cadmium being substantially the same 13a) the observed atomic ratio to stannum.Additionally, the XPS in Figure 13 b Profile confirms the existence after stepping back step with the cadmium depleted region of about 50nm thickness.

Figure 14-16 is shown respectively to arrange as autotransformer Unit), the sheet resistance of the CTO film of the RTA annealing of the function of pulse width and lamp power Value.The electrical properties of the CTO film of Figure 14-16 diagram RTA annealing can be by changing for RTA Technological parameter and control.

The CTO layer that example 2 rapid thermal annealing is arranged on soda-lime glass

Use ceramic target and the sputtering pressure of 16 millitorrs, sputter at soda-lime glass by room temperature DC Three films of CTO are prepared on supporter.This soda-lime glass supporter has about 3.2mm's Thickness.CTO film on soda-lime glass supporter uses such as side described in the example 1 above Method experience RTA.But, for the CTO film being arranged on soda-lime glass supporter, use 3 to 4 quick thermal annealing process are repeated for each circulation pulse width of 30 seconds.Move back The total duration of fire step is about 2 minutes.

Figure 17 illustrates and circulates the development towards the optical clarity improved with each continuous annealing.Sodium The slower annealing rate of the CTO film on lime glass can be due to thicker soda-lime glass supporter (3.2mm) causing, it causes different heat distributions to occur (when the boron with thinner (1.3mm) When silicate glass supporter is compared).

Figure 18 is shown through the XRD style of three samples of RTA annealing, and it illustrates amorphous CTO is converted into the cubic spinel type phase of crystallization.RTA is used to form knot on soda-lime glass Even if the proof of brilliant CTO represents realizes temperature range during RTA step at 800-900 DEG C Between, it is possible to obtain crystallization CTO film and not apparent damage to soda-lime glass supporter. As indicated earlier, soda-lime glass is that more economical supporter selects, but because its softening temperature Degree is more than 550 DEG C, and it closes on annealing process (～630 DEG C) as the use of supporter at CdS Middle eliminating.

The average sheet resistance of the CTO film of the RTA annealing being arranged on sodium calcium supporter is 7.6 ± 0.9 ohm-sq, putting down of its a little higher than CTO film being arranged on borosilicate glass All sheet resistances (7.1 ± 0.2ohms/square).

Example above is merely exemplary, play only demonstration inventive feature in some Effect.The claim enclosed is intended to as have already envisaged for broadly claim the present invention And presented herein illustrate from likely embodiment set the embodiment that selects. Therefore, the claim enclosed that is intended that of applicant is not subject to for inventive feature is described The restriction of example selection.As used in the claims, word " includes " and it is in logic On grammatical variants further relate to and include having change and phrase in various degree, such as But be not limited to " substantially by ... constitute " and " by ... composition ".In the case of necessary, carry Supply scope；Those scopes include all subranges therebetween.In these scopes anticipated, change will Enlighten those skilled in that art and be not also devoted to the local practitioner of the public, as possible, Those change claim should being construed to by enclosing contain.It is also contemplated that the entering of Science and Technology Equivalent and replacement that step will make the inaccuracy due to language and is not contemplated to now are possibly realized, And as possible, these change claim also should being construed to by enclosing contain.

Claims (27)

1. for the method forming cadmium tin oxide layer, comprising:

Supporter arranges the cadmium tin oxide layer of amorphous；And

By the first surface of the cadmium tin oxide layer of described amorphous is exposed to electromagnetic radiation, the cadmium tin oxide layer rapid thermal annealing of described amorphous is formed clear layer,

Wherein rapid thermal annealing includes the cadmium tin oxide layer of described amorphous is exposed to the one or more irrelevant light source selected from the group that Halogen light, uviol lamp, high-intensity discharge lamp and combinations thereof are constituted, and

Wherein rapid thermal annealing includes in the persistent period from 10 seconds to 40 second scopes, the cadmium tin oxide layer of described amorphous is exposed to described electromagnetic radiation.

2. the method for claim 1, wherein rapid thermal annealing includes with more than 200 watts/cm²Scope in incident power densities irradiation described in the described first surface of cadmium tin oxide layer of amorphous.

3. the method for claim 1, wherein said electromagnetic radiation includes the radiation of infra-red radiation, ultraviolet or a combination thereof.

4. the method for claim 1, wherein said electromagnetic radiation has less than the wavelength in 600nm scope.

5. the method for claim 1, wherein said electromagnetic radiation has the wavelength from 450nm to 600nm scope.

6. the method for claim 1, wherein said electromagnetic radiation has less than the wavelength in 300nm scope.

7. the method for claim 1, the treatment temperature that wherein rapid thermal annealing is included in from 700 DEG C to 1000 DEG C scopes heats the cadmium tin oxide layer of described amorphous.

8. the method for claim 1, wherein rapid thermal annealing includes with the cadmium tin oxide layer of amorphous described in the heating rate more than 20 DEG C/s.

9. the method for claim 1, wherein rapid thermal annealing includes that the first surface of the cadmium tin oxide layer by described amorphous is exposed to described electromagnetic radiation in the atmosphere including oxygen, argon, nitrogen, hydrogen, helium or a combination thereof.

10. the method for claim 1, the cadmium tin oxide layer being provided with described amorphous includes sputtering, chemical gaseous phase deposition, spin coating or dip-coating.

11. the method for claim 1, wherein said supporter has less than the softening temperature in 600 DEG C of scopes, and the treatment temperature that wherein rapid thermal annealing is included in from 700 DEG C to 1000 DEG C scopes heats the cadmium tin oxide layer of described amorphous.

12. the method for claim 1, wherein said supporter includes borosilicate glass or soda-lime glass.

13. the method for claim 1, wherein said clear layer includes the cadmium tin with single-phase spinel type crystal structure.

14. the method for claim 1, wherein said clear layer includes:

A () includes the first area of cadmium tin；With

B () includes the second area of stannum and oxygen, the cadmium atomic concentration in wherein said second area is less than the cadmium atomic concentration in described first area.

15. methods as claimed in claim 14, the cadmium atomic concentration in wherein said second area is less than 20%.

16. methods as claimed in claim 14, wherein said second area does not has cadmium.

17. methods as claimed in claim 14, wherein said second area has the resistivity of the resistivity more than described first area.

18. methods as claimed in claim 14, it farther includes the transition region between described first area and described second area, wherein said transition region includes that in cadmium, stannum and oxygen, and described transition region, the atomic ratio of stannum is changed by cadmium across the thickness of described transition region.

19. the method for claim 1, wherein said clear layer has at the thickness from 100nm to 600nm scope.

20. the method for claim 1, wherein said clear layer has less than 2x10^-4The resistivity of ohm-cm.

21. the method for claim 1, wherein said clear layer has the average optical absorbance more than 80%.

22. 1 kinds are used for the method forming photovoltaic device, comprising:

Supporter arranges the cadmium tin oxide layer of amorphous；And

By the first surface of the cadmium tin oxide layer of described amorphous is exposed to electromagnetic radiation, the cadmium tin oxide layer rapid thermal annealing of described amorphous is formed clear layer；

Described clear layer arranges the first semiconductor layer；

Described first semiconductor layer arranges the second semiconductor layer；And

Described second semiconductor layer arranges back contact to form photovoltaic device,

Wherein rapid thermal annealing includes in the persistent period from 10 seconds to 40 second scopes, the cadmium tin oxide layer of described amorphous is exposed to described electromagnetic radiation.

23. methods as claimed in claim 22, wherein said first semiconductor layer includes cadmium sulfide.

24. methods as claimed in claim 22, wherein said second semiconductor layer includes cadmium telluride.

25. methods as claimed in claim 22, it further includes at and arranges cushion between described clear layer and described first semiconductor layer.

26. methods as claimed in claim 25, wherein said cushion includes the oxide selected from the group that stannum oxide, Indium sesquioxide., zinc oxide and a combination thereof are constituted.

27. 1 kinds are used for the method forming cadmium tin oxide layer, comprising:

Supporter arranges the cadmium tin oxide layer of amorphous, and

By the first surface of the cadmium tin oxide layer of described amorphous is exposed to electromagnetic radiation, described amorphous oxide cadmium tin layers rapid thermal annealing is formed clear layer；

Wherein said clear layer includes the cadmium tin with single-phase spinel type crystal structure, and described clear layer has less than 2x10^-4The resistivity of ohm-cm, and

Wherein said rapid thermal annealing includes in the persistent period from 10 seconds to 40 second scopes, the cadmium tin oxide layer of described amorphous is exposed to described electromagnetic radiation.