TW201535757A - Manufacturing method of absorption layer in thin-film solar cell and manufacturing method of thin-film solar cell - Google Patents

Abstract

A manufacturing method of absorption layer in thin-film solar cell includes the following steps: (a) providing copper alloy particles as shown in formula (I), CuInxGayStSeu; (b) using electron beam to act on the copper alloy particles as shown in formula (I) in a vacuum environment so as to soften the copper alloy particles as shown in formula (I) to form the softened copper alloy as shown in formula (I); and, (c) continuously using electron beam in cooperation with ion beam to gasify the softened copper alloy as shown in formula (I) so as to form an absorption layer on a substrate. Compared to the selenization and magnetron sputtering method, the manufacturing method of absorption layer according to the present invention can be conducted in an environment temperature of 25 degree C to 200 degree C so as to greatly reduce the power consumption and eliminate the annealing process. All of the functional layers in the thin-film solar cell according to the present invention are formed by electron beam in cooperation with ion beam.

Description

Method for manufacturing absorption layer in thin film solar cell and thin Film solar cell manufacturing method

The present invention relates to an absorption layer and a method for fabricating a thin film solar cell in a thin film solar cell, and more particularly to a method for fabricating an absorption layer using an electron beam and an ion beam, and a thin film solar cell.

Thin film solar cells are roughly classified into germanium thin film solar cells, cadmium telluride (CdTe) solar cells, and copper indium gallium selenide [Cu(In,Ga)(Se,S)] thin film solar cells, among which copper indium gallium Selenium thin film solar cells are widely recognized because of their high photo-to-current conversion efficiency (PCE), low manufacturing cost, high product quality, simple process, high process safety, and no pollution to the environment. .

At present, a preparation method of a copper indium gallium selenide film in a copper indium gallium selenide thin film solar cell generally has a co-evaporation method, a selenization method, and a magnetron sputtering method.

The co-evaporation method uses a copper source, an indium source, a gallium source, and a selenium source as evaporation sources, respectively. The method needs to monitor the film thickness and the evaporation rate of the evaporation source from time to time to obtain a good quality copper indium gallium selenide film, however, The vapor pressures of the evaporation source are different, which makes it difficult to control the content of copper, indium, gallium and selenium in the copper indium gallium selenide film, resulting in the inability to obtain a uniform quality copper indium gallium selenide film, and using the method. The obtained copper indium gallium selenide film is applied to a solar cell, and the photoelectric conversion conversion rate of the solar cell still needs to be improved.

The selenization process is very complicated, and the selenization temperature is high (at least 550 ° C or more), and the energy consumption is large. Furthermore, this method requires the use of toxic hydrogen selenide (H ₂ Se) gas, which is low in safety, and the excess hydrogen selenide gas after film formation is difficult to handle, resulting in problems of cost increase and yield reduction.

The magnetron sputtering method consumes a large amount of energy, and the soda-lime glass substrate used in the surface is slightly melted at a temperature above 550 ° C, resulting in deformation, which is not conducive to the formation of a copper indium gallium selenide film, and needs to be annealed again. . Moreover, the bombarded high-speed anode target atoms or molecules easily cause surface damage of the copper indium gallium selenide film.

According to the above description, it is known that the method for fabricating a copper indium gallium selenide layer having low energy consumption and not requiring annealing treatment, and the method for fabricating the thin film solar cell are required for improvement in the technical field.

Accordingly, a first object of the present invention is to provide a method of fabricating an absorbing layer in a thin film solar cell having low energy consumption and which does not require annealing.

Therefore, the method for fabricating the absorption layer in the thin film solar cell of the present invention comprises the steps of: (a) providing a copper-based alloy particle of the formula (I), CuIn _x Ga _y S _t Se _u (I)

In the formula (I), x, y, t and u each represent 0 to 1, wherein x+y and t+u are each greater than 0; (b) in a vacuum environment, the electron beam is used for the formula (I) The copper-based alloy particles shown act to soften the copper-based alloy particles represented by the formula (I) to form a softened copper-based alloy of the formula (I); (c) continuously use an electron beam and match the ion beam The copper-based alloy represented by the formula (I) is vaporized to form an absorption layer on a substrate.

When the electron beam is continuously used to vaporize the softened copper-based alloy represented by the formula (I), the energy of the electron beam is controlled so that the vaporized copper-based alloy represented by the formula (I) maintains each element. The absorption layer is formed on the substrate in proportion, and then the softened copper-based alloy represented by the formula (I) is prevented from decomposing and being deteriorated, resulting in a change in the ratio of each element in the absorption layer.

Preferably, x:y:(t+u) is 1:1:2.

Preferably, when the copper-based alloy particles represented by the formula (I) are acted upon by an electron beam, the copper-based alloy particles represented by the formula (I) are softened by a moving scanning method.

Preferably, the total content of the chemical equivalent of indium and gallium is 1 equivalent, the content of the copper is in the range of 0.8 to 0.95 equivalent, the content of the gallium is in the range of 0.2 to 0.3 equivalent, and the content of the selenium is in the range of 0.45 equivalents to 0.55 equivalents.

Preferably, the degree of vacuum ranges from 1 x 10 ^-4 Torr to 5 x 10 ^-7 Torr.

Preferably, the ambient temperature ranges from 25 ° C to 200 ° C.

Preferably, the electron beam has a power supply ranging from 1,000 watts (Walt) to 9,000 watts. Preferably, the electron beam has a voltage in the range of 1,000 volts (Volt) to 6,000 volts. Preferably, the ion beam has a power supply ranging from 500 watts to 3,000 watts.

Preferably, the thickness of the absorbing layer ranges from 1.2 μm to 4 μm. The thickness of the absorbing layer can be accomplished in one or several steps, wherein the completion of the division means the formation of a plurality of absorbing layers. Preferably, the content of gallium in the copper-based alloy represented by the formula (I) of any of the absorption layers is different, and the content of gallium in each of the absorption layers from the substrate is sequentially decreased and the indium content is sequentially increased. .

The electron beam device is provided such as, but not limited to, an electron gun or a tungsten filament.

The ion beam device is provided, for example, but not limited to, an ion source device or a plasma device.

The substrate is, for example but not limited to, soda lime glass, a polyimide substrate or a polyethylene terephthalate substrate.

A second object of the present invention is to provide a method of fabricating a thin film solar cell.

Therefore, the method for fabricating the thin film solar cell of the present invention comprises the steps of: (a) providing a substrate; (b) providing a metal source for the first electrode; using the copper alloy particles of the formula (I) for the absorption layer, and a buffer layer A Group II-VI chalcogenide, a zinc oxide-based material for a transparent conductive layer, and a metal source for a second electrode, wherein the second electrode metal source comprises at least one metal consisting of: nickel and aluminum ,CuIn _x Ga _y S _t Se _u (I)

In the formula (I), x, y, t and u each represent 0 to 1, wherein x+y and t+u are respectively greater than 0; (c) in a vacuum environment, using an electron beam and an ion beam in sequence The metal source for the first electrode, the copper-based alloy particles represented by the formula (I), the II-VI chalcogenide for the buffer layer, the zinc oxide-based material for the transparent conductive layer, and the metal source for the second electrode And forming a first electrode, an absorbing layer, a buffer layer, a transparent conductive layer, and a second electrode sequentially on the substrate.

The substrate, the electron beam apparatus, and the ion beam apparatus are as described above, and thus will not be described again.

Preferably, the electron beam has a power supply ranging from 1,000 watts (Walt) to 9,000 watts. Preferably, the electron beam has a voltage in the range of 1,000 volts (Volt) to 6,000 volts. Preferably, the ion beam has a power supply ranging from 500 watts to 3,000 watts. Preferably, the degree of vacuum ranges from 1 x 10 ^-4 Torr to 5 x 10 ^-7 Torr. Preferably, the ambient temperature ranges from 25 ° C to 200 ° C.

The first electrode metal source is, for example but not limited to, metal molybdenum. Preferably, the power source of the electron beam acting on the first electrode with a metal source ranges from 5,000 watts to 9,000 watts. Preferably, the power source of the ion beam acting on the first electrode with a metal source ranges from 500 watts to 3,000 watts. Preferably, in the process of forming the first electrode, the degree of vacuum ranges from 1 × 10 ^-4 Torr to 5 × 10 ^-6 Torr. Preferably, the ambient temperature ranges from 40 ° C to 200 ° C during the formation of the first electrode. Preferably, the thickness of the first electrode ranges from 0.05 μm to 3 μm. The thickness of the first electrode can be completed in one or several steps, wherein the completion of the division means the formation of a plurality of first electrodes.

Preferably, the electron beam power of the electron beam acting on the copper-based alloy particles represented by the formula (I) ranges from 5,000 watts to 9,000 watts. Preferably, the power source of the ion beam acting on the copper-based alloy particles represented by the formula (I) ranges from 1,000 watts to 3,000 watts. Preferably, in the process of forming the absorbing layer, the degree of vacuum ranges from 1 × 10 ^-5 Torr to 5 × 10 ^-7 Torr. Preferably, the ambient temperature ranges from 50 ° C to 200 ° C during the formation of the absorbing layer. Preferably, the thickness of the absorbing layer ranges from 1.2 μm to 4 μm.

Preferably, x:y:(t+u) is 1:1:2.

Preferably, when the copper-based alloy particles represented by the formula (I) are acted upon by an electron beam, the copper-based alloy particles represented by the formula (I) are softened by a moving scanning method.

Preferably, the total content of the chemical equivalent of indium and gallium is 1 equivalent, the content of the copper is in the range of 0.8 to 0.95 equivalent, the content of the gallium is in the range of 0.2 to 0.3 equivalent, and the content of the selenium is in the range of 0.45 equivalents to 0.55 equivalents.

Preferably, the thickness of the absorbing layer ranges from 1.2 μm to 4 μm. The thickness of the absorbing layer can be accomplished in one or several steps, wherein the completion of the division means the formation of a plurality of absorbing layers. Preferably, the gallium content of the copper-based alloy represented by the formula (I) of any of the absorption layers is different, and each of the absorption layers from the substrate The gallium content in the order is decreasing sequentially and the indium content is increasing sequentially.

The buffer layer is a Group II-VI chalcogenide such as, but not limited to, zinc sulfide (ZnS) or cadmium sulfide (CdS). Preferably, the power beam of the electron beam acting on the buffer layer with a Group II-VI chalcogenide ranges from 1,000 watts to 5,000 watts. Preferably, the ion beam of the buffer layer with a Group II-VI chalcogenide has a power source ranging from 500 watts to 1,000 watts. Preferably, in the process of forming the buffer layer, the degree of vacuum ranges from 5 × 10 ^-4 Torr to 1 × 10 ^-5 Torr. Preferably, the ambient temperature ranges from 50 ° C to 200 ° C during the formation of the buffer layer. Preferably, the buffer layer has a thickness ranging from 10 nm to 100 nm.

The transparent conductive layer is made of a zinc oxide-based material such as, but not limited to, intrinsic zinc oxide (intrinsic ZnO) or aluminum source doped zinc oxide (Al-doped ZnO). The aluminum source is for example but not limited to metallic aluminum or aluminum oxide (Al ₂ O ₃ ). The transparent conductive layer is one or two or more layers. When the transparent conductive layer is two or more layers, the transparent conductive layers are the same or different. Preferably, in the process of forming the transparent conductive layer, the degree of vacuum ranges from 5 × 10 ^-4 Torr to 1 × 10 ^-5 Torr. Preferably, the ambient temperature ranges from 60 ° C to 200 ° C during the formation of the zinc oxide layer.

Preferably, the power source of the electron beam acting on the intrinsic zinc oxide ranges from 1,000 watts to 5,000 watts. Preferably, the ion beam of the intrinsic zinc oxide has a power source ranging from 500 watts to 2,000 watts. Preferably, the intrinsic zinc oxide layer has a thickness ranging from 15 nm to 100 nm.

Preferably, the electron beam of the aluminum source is doped with zinc oxide Power supplies range from 1,000 watts to 5,000 watts. Preferably, the ion beam of the aluminum source doped with zinc oxide has a power supply ranging from 1,000 watts to 3,000 watts. Preferably, the aluminum source doped zinc oxide layer has a thickness ranging from 150 nm to 500 nm.

The second electrode can be formed by a method of forming an electrode in a conventional thin film solar cell, or by using an electron beam and an ion beam to act as a metal source for the second electrode. Preferably, the power source of the electron beam acting on the second electrode with a metal source ranges from 3,000 watts to 8,000 watts. Preferably, the power source of the ion beam acting on the second electrode with a metal source ranges from 1,000 watts to 3,000 watts. Preferably, in the process of forming the second electrode, the degree of vacuum ranges from 5 × 10 ^-5 Torr to 5 × 10 ^-6 Torr. Preferably, the ambient temperature ranges from 60 ° C to 180 ° C during the formation of the second electrode. Preferably, the thickness of the second electrode ranges from 300 nm to 5,000 nm.

Preferably, the method for fabricating the thin film solar cell further comprises the step of forming a magnesium fluoride layer on the transparent conductive layer before forming the second electrode. The formation method of the magnesium fluoride layer can be formed by a method of forming a magnesium fluoride layer in a conventional thin film solar cell, or by using an electron beam and an ion beam to act on magnesium fluoride. Preferably, the power beam of the electron beam acting on the magnesium fluoride ranges from 1,000 watts to 5,000 watts. Preferably, the ion beam of the magnesium fluoride has a power source range of from 500 watts to 2,000 watts. Preferably, in the process of forming the magnesium fluoride layer, the degree of vacuum ranges from 5 × 10 ^-4 Torr to 1 × 10 ^-5 Torr. Preferably, the ambient temperature ranges from 60 ° C to 150 ° C during the formation of the magnesium fluoride layer. Preferably, the magnesium fluoride layer has a thickness ranging from 60 nm to 200 nm.

The invention has the effect that the preparation method of the absorption layer of the invention uses the electron beam and the ion beam, and the formation of the absorption layer can be carried out at an ambient temperature of 25 ° C to 200 ° C, thereby greatly reducing the energy consumption, and does not need to be annealed. . Further, each functional layer in the thin film solar cell of the present invention is formed by using an electron beam with an ion beam.

Metal molybdenum, Cu ₁ In _0.7 Ga _0.3 Se ₂ alloy particles, zinc sulfide, intrinsic zinc oxide, aluminum-doped zinc oxide, magnesium fluoride, metallic nickel, and metallic aluminum are respectively placed in eight turntables, and the turntable is placed It is placed in a vacuum furnace with a regulated temperature and a vacuum.

Set the ambient temperature and vacuum to 180 ° C and 1 × 10 ^-4 Torr, respectively, using 6000 watts of electron gun power (label: Win Glory; model: WG-10E) and 2000 watts of ion source power (factory) Brand: Win Glory; Model: WG-3I) The action of metal molybdenum evaporates the metal molybdenum and deposits a 0.1 μm first molybdenum electrode on a soda glass substrate. Next, the degree of vacuum was set to 5 × 10 ^-5 Torr and the above steps were repeated, and a second molybdenum electrode of 0.95 μm was further deposited on the first molybdenum electrode. The molybdenum electrodes formed are used as back electrodes in solar cells. The second molybdenum electrode is intended to reduce the electrical resistance of the back electrode to provide good ohmic contact with the subsequently formed absorber layer.

The ambient temperature and the degree of vacuum were set to 180 ° C and 1 × 10 ^-5 Torr, respectively, and a 200 watt electron gun power supply was used for the Cu ₁ In _0.7 Ga _0.3 Se ₂ alloy particles (the content of copper was 1.00 equivalent, and the content of indium was 0.7). Equivalent, gallium content of 0.3 equivalents, and selenium content of 2.00 equivalents, softening the Cu ₁ In _0.7 Ga _0.3 Se ₂ alloy particles, followed by using 4,000 watts of electron gun power and 1,000 watts of ion source power, respectively. the power softened Cu ₁ in _0.7 Ga _0.3 Se ₂ alloy effect, so that the softened Cu ₁ in _0.7 Ga _0.3 Se ₂ alloy gasification, a 2μm deposited absorber layer on the second electrode of molybdenum. The resulting absorber layer is used as a P-type absorber layer in a solar cell.

After the formation of the absorption layer, the ambient temperature and the degree of vacuum were set to 180 ° C and 1 × 10 ^-5 Torr, respectively, and the zinc sulfide was applied with a power of 2,000 watts of electron gun power and an ion source power of 1,000 watts, respectively, to effect the vulcanization. Zinc evaporates and a 50 nm layer of zinc sulfide is deposited on the absorber layer. The formed zinc sulfide layer is used as an N-type buffer layer in a solar cell.

After the formation of the zinc sulfide layer, the ambient temperature and the degree of vacuum were set to 150 ° C and 1 × 10 ^-5 Torr, respectively, using an electron gun power of 1,500 watts and an ion source power of 1,000 watts to effect the intrinsic zinc oxide. The intrinsic zinc oxide evaporates and a 50 nm intrinsic zinc oxide layer is deposited on the zinc sulfide layer. The intrinsic zinc oxide layer formed is used as a transparent conductive layer in a solar cell to increase the light transmittance of the solar cell.

After forming the intrinsic zinc oxide layer, the ambient temperature and the vacuum were set to 150 ° C and 5 × 10 ^-5 Torr, respectively, using 2,000 watts of electron gun power and 1,000 watts of ion source power for aluminum-doped zinc oxide. The aluminum-doped zinc oxide is evaporated, and a 500 nm aluminum-doped zinc oxide layer is deposited on the intrinsic zinc oxide layer. The formed aluminum-doped zinc oxide layer is used as a transparent conductive layer in a solar cell to increase the light transmittance of the solar cell.

After forming an aluminum-doped zinc oxide layer, the ambient temperature and the degree of vacuum were set to 120 ° C and 5 × 10 ^-5 Torr, respectively, and the magnesium fluoride was supplied using Watt's 2,000 electron gun power supply and 1,000 watts of ion source power. The energy is such that the magnesium fluoride is evaporated, and a 100 nm magnesium fluoride layer is deposited on the aluminum-doped zinc oxide layer. The formed magnesium fluoride layer is used as a reflective layer in a solar cell.

After forming the magnesium fluoride layer, the ambient temperature and the degree of vacuum were set to 180 ° C and 5 × 10 ^-5 Torr, respectively, and the metal nickel was energized using an electron gun power of 5,000 watts and an ion source power of 2,000 watts, respectively. The metallic nickel evaporates and a 100 nm metallic nickel layer is deposited on the magnesium fluoride layer.

After the formation of the metallic nickel layer, the ambient temperature and the degree of vacuum were set to 180 ° C and 5 × 10 ^-5 Torr, respectively, and the metal aluminum was energized using an electron gun power of 5,000 watts and an ion source power of 2,000 watts, respectively. The aluminum metal evaporates and a 1 μm layer of metal aluminum is deposited on the metallic nickel layer. The formed metallic nickel layer and metallic aluminum layer are used as the upper second electrode in the solar cell.

In summary, the absorbing layer of the present invention can be produced at 25 ° C. It is carried out at an ambient temperature of 200 ° C, which in turn greatly reduces the energy consumption and does not require annealing. The method for fabricating the absorber layer of the present invention can be carried out at an ambient temperature of from 25 ° C to 200 ° C, which in turn greatly reduces energy consumption and does not require annealing. On the other hand, each functional layer in the thin film solar cell of the present invention is formed by using an electron beam with an ion beam, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

Claims (10)

A method for fabricating an absorption layer in a thin film solar cell, comprising the steps of: (a) providing a copper-based alloy particle of the formula (I), CuIn _x Ga _y S _t Se _u (I) in the formula (I), x, y, t, and u each represent 0 to 1, wherein x+y and t+u are each greater than 0; (b) using a electron beam to the copper alloy of the formula (I) in a vacuum environment The particles act to soften the copper-based alloy particles of the formula (I) to form a softened copper-based alloy of the formula (I); (c) continuously use an electron beam and match the ion beam to make the softening formula The copper-based alloy shown in (I) is vaporized to form an absorbing layer on a substrate. The method for producing an absorption layer in a thin film solar cell according to claim 1, wherein the content of the copper is from 0.8 equivalent to 0.95 equivalent, and the content of the gallium is 1 equivalent of the total equivalent amount of the indium and gallium. The range is from 0.2 equivalents to 0.3 equivalents, and the content of the selenium ranges from 0.45 equivalents to 0.55 equivalents. The method for fabricating an absorption layer in a thin film solar cell according to claim 1, wherein the electron beam has a power supply ranging from 1,000 watts to 9,000 watts. The method for fabricating an absorption layer in a thin film solar cell according to claim 1, wherein the ion beam has a power supply ranging from 500 watts to 3,000 watts. The method for producing an absorption layer in a thin film solar cell according to claim 1, wherein the degree of vacuum ranges from 1 × 10 ^-4 Torr to 5 × 10 ^-7 Torr. A method for fabricating a thin film solar cell, comprising the steps of: (a) providing a substrate; (b) providing a metal source for the first electrode; and using the copper alloy particles of the formula (I) for the absorption layer; a Group VI chalcogenide, a zinc oxide-based material for a transparent conductive layer, and a metal source for a second electrode, wherein the second electrode metal source comprises at least one metal consisting of nickel and aluminum, CuIn _x Ga _y S _t Se _u Formula (I) In the formula (I), x, y, t and u each represent 0 to 1, wherein x+y and t+u are respectively greater than 0; (c) in a vacuum In the environment, the metal source for the first electrode, the copper-based alloy particles represented by the formula (I), the II-VI chalcogenide for the buffer layer, and the transparent conductive layer are sequentially oxidized using an electron beam and an ion beam. The zinc-based material acts to form a first electrode, an absorbing layer, a buffer layer, a transparent conductive layer, and a second electrode sequentially on the substrate. The method for fabricating a thin film solar cell according to claim 6, wherein the content of the copper ranges from 0.8 equivalents to 0.95 equivalents, and the content of the gallium ranges from 0.2 to 1 equivalent of the total equivalent amount of the indium and gallium. The equivalent weight is 0.3 equivalents, and the content of the selenium ranges from 0.45 equivalents to 0.55 equivalents. The method of fabricating a thin film solar cell according to claim 6, wherein the electron beam has a power supply ranging from 1,000 watts to 9,000 watts. The method of fabricating a thin film solar cell according to claim 6, wherein the degree of vacuum ranges from 1 × 10 ^-4 Torr to 5 × 10 ^-7 Torr. The method of fabricating a thin film solar cell according to claim 6, wherein the ion beam has a power supply ranging from 500 watts to 3,000 watts.