WO2017043704A1 - Ultraviolet photodetector and method for manufacturing same - Google Patents

Ultraviolet photodetector and method for manufacturing same Download PDF

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WO2017043704A1
WO2017043704A1 PCT/KR2015/013790 KR2015013790W WO2017043704A1 WO 2017043704 A1 WO2017043704 A1 WO 2017043704A1 KR 2015013790 W KR2015013790 W KR 2015013790W WO 2017043704 A1 WO2017043704 A1 WO 2017043704A1
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layer
transparent conductive
bonding layer
ultraviolet
photodetector
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PCT/KR2015/013790
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French (fr)
Korean (ko)
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김준동
파텔말케시쿠마르
김홍식
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인천대학교 산학협력단
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED, VISIBLE OR ULTRA-VIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00Photometry, e.g. photographic exposure meter
    • G01J1/42Photometry, e.g. photographic exposure meter using electric radiation detectors
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R1/00Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
    • G01R1/02General constructional details
    • G01R1/06Measuring leads; Measuring probes
    • G01R1/067Measuring probes
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02Details
    • H01L31/0236Special surface textures
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/036Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes
    • H01L31/0392Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/09Devices sensitive to infra-red, visible or ultraviolet radiation
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/10Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by at least one potential-jump barrier or surface barrier, e.g. phototransistors
    • H01L31/101Devices sensitive to infra-red, visible or ultra-violet radiation
    • H01L31/102Devices sensitive to infra-red, visible or ultra-violet radiation characterised by only one potential barrier or surface barrier
    • H01L31/109Devices sensitive to infra-red, visible or ultra-violet radiation characterised by only one potential barrier or surface barrier the potential barrier being of the PN heterojunction type
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy

Abstract

An ultraviolet photodetector and a method for manufacturing the same are provided. The ultraviolet photodetector comprises: a substrate; a transparent conductive layer formed on the substrate; and a heterojunction layer comprising a first junction layer of a first conductive type, which is formed on the transparent conductive layer, and a second junction layer of a second conductive type, which is different from the first conductive type, the second junction layer constituting a heterojunction with the first junction layer.

Description

Ultraviolet photodetector and a method of manufacturing the same

The present invention relates to an ultraviolet photodetector and a method of manufacturing the same, and more particularly to high light reactivity, the reaction rate is related to rapid ultraviolet photodetector and a method of manufacturing the same.

Essentially, NiO is a wide direct band gap (3.6 - 4.3 eV), and have, a low-cost, abundant on earth and the great nature-then the p-type semiconductor material suitable for the application of photo electric devices. A wide bandgap semiconductor, NiO has a widespread use ZnO (60 meV), GaN (26 meV), or ZnSe (20 meV) of the high exciton binding 110meV from the same semiconductor material and the energy (Exciton binding energy) is. Further, the high binding energy also means that the stability of the device for the thermal energy at room temperature (26 meV).

Further, extremely thin NiO is 1.33 eV to - have proven to be effective with the electron blocking capability and hole transport functions within the optoelectronic device by the low electron affinity of 1.85 eV FIG.

By such a wide range of material properties, NiO may be used in various applications. For example, NiO energy conversion (organic solar cells (organic solar cells) anode buffer layer (Anode buffer layer), the transparent solar cell (transparent solar cells), piezoelectric nano-generator (piezoelectric nano-generator) and a photoelectric chemical cell (photoelectrochemical of cells), and so on), energy storage (Li-ion batteries (Li-ion batteries), rechargeable battery and a second battery (supercapacitors), etc.), photo-generated (Yes Sons light emitting device and a two-sided electroluminescence (double side electroluminescence), etc.), e circuit may be used for (the transparent conductive layer, a transparent diode, and switching, memory and logic circuitry, etc.), and energy sensing (gas sensing, multispectral photodetector (photodetectors multispectral) and ultraviolet photodetector, etc.).

The problem to be solved by the present invention is to provide an optical response time improving the ultraviolet photodetector.

Another object is to photoreaction rate is provide improved ultraviolet photodetector manufacturing method to be solved by the present invention.

Another problem to be solved by the present invention is to provide an improved optical response speed is ultraviolet photo-di tekting method.

Not limited to the described problems are referred to above to be solved by the present invention, task, another task that are not mentioned will be understood clearly to those skilled in the art from the following description.

A transparent conductive layer is formed on the transparent conductive layer, a first bonding layer of a first conductivity type UV photodetector according to an embodiment of the present invention for solving the foregoing problems is to be formed on the substrate, the substrate and, It includes a heterojunction layer including the first joining layer and the second bonding layer of a heterojunction (hetero junction) of the first conductivity type different from the second conductivity type constituting the.

UV photodetector manufacturing method according to an embodiment of the present invention for solving the other problems is to form a transparent conductive layer on a substrate, and forming the first bonding layer of a first conductivity type on the transparent conductive layer, It comprises the first to the bonding layer and a metal layer is formed, by thermal oxidation (rapid thermal oxidation) rapidly to the metal layer to form a second joining layer.

The additional challenge UV, according to one embodiment of the present invention for solving the photo-di tekting method the substrate and the transparent conductive layer formed on the substrate, a first conductivity type formed on the transparent conductive layer 1 providing the first bonding layer and a heterojunction (hetero junction) for forming an ultraviolet detection, including a second bonding layer of the other second conductivity type and first conductivity type devices on the bonding layer and the first bonding layer, and , it involves the incident ultraviolet light to the ultraviolet sensors, and in contact with the first probe directly on the upper surface of the transparent conductive layer, detects the ultraviolet radiation in contact with a second probe directly on the upper surface of the second bonding layer.

Specific details of other embodiments are included in the following description and drawings.

In one embodiment of the invention it has at least the following effects.

That is, the UV photodetector according to an embodiment of the present invention can have a significantly fast optical response speed compared with the conventional photodetector.

In addition, UV photodetector according to an embodiment of the present invention can detect ultraviolet radiation without the need for much external metal electrode.

Further, the UV photodetector according to an embodiment of the present invention may have a high performance with respect to the UV-A region of the long wavelength of the ultraviolet region.

Effect according to the present invention is not limited by the details illustrated in the above, and is more diverse effects are included in the present specification.

1 is a perspective view for explaining an ultraviolet photodetector according to an embodiment of the present invention.

2 is a view showing the Example 1, Comparative Examples 1 and 2 X-ray diffraction (X-ray diffraction, XRD) pattern of the present invention.

3 is an isometric drawing of the cubic unit cell for explaining the structure of the molecules of the present invention NiO.

Figure 4 is a sectional view taken in AA in Fig.

Figure 5 is an enlarged view of B part of Fig.

6 is a graph for explaining the transmission rate according to help absorption of Comparative Examples 1 to 3 of the present invention wavelength.

7 is a graph illustrating an absorption coefficient α according to the photon energy of Comparative Example 1 and Comparative Example 2 of the present invention.

Figure 8 is a graph tau (Tauc plot) for comparison of Comparative Examples 1 and 2 of the present invention.

Figure 9 is a graph showing the intensity of light according to the wavelength for illustrating the optical luminescence (photoluminescence, PL) of the NiO film.

10 is a view for explaining the method of the ultraviolet-di tekting UV photodetector according to an embodiment of the present invention.

11 and 12 are views showing a voltage-current curve of the dark current in the condition of the UV photodetector according to an embodiment of the present invention.

13 to 15] A view to describe a reaction in the reverse bias of a UV photodetector according to an embodiment of the present invention.

16 and 17 is an energy band diagram at the interface between the first and the second bonding layer of a UV photodetector according to an embodiment of the present invention.

18 to 21 are intermediate view illustrating a UV photodetector manufacturing method according to an embodiment of the present invention.

Methods of accomplishing the advantages and features of the present invention and reference to the embodiments that are described later in detail in conjunction with the accompanying drawings will be apparent. However, the invention is not limited to the embodiments set forth herein be embodied in many different forms, only, and the present embodiments are to complete the disclosure of the present invention, ordinary skill in the art will to those provided to indicate that the full scope of the invention, the present invention will only be defined by the appended claims. Like reference numerals throughout the specification refer to like elements.

Although the first, second, etc. are used, but in order to describe various elements, components, and / or sections, these elements, components, and / or sections are not limited by these terms. FIG. These terms are only used to the one element, component, or section, in order to distinguish it from other elements, components, or sections. Thus, a first element, a first element or a first section which is referred to hereafter which may be a second element, the second component, or second section, within the spirit of the invention.

Element a case where it (elements) or layer is referred to as the other element or layer "above (on)", or "the (on)", as well as directly over the other element or layer through the other layer or the other element in the middle The all-inclusive. On the other hand, it indicates that the element is referred to as "directly above (directly on)" or "directly over" another element or layer is not interposed in the middle.

As spatially relative terms a "down (below)", "down (beneath)", "bottom (lower)", "upper (above)", "top (upper)", etc. are shown in the drawings a a correlation with the element or component and another element or component relationships can be used to easily described. Spatially relative terms are to be in addition to the direction illustrated in the drawing understood to those containing the different directions of the device during use or operation. For example, when the flip element is shown in the figure, the element described as "below (below or beneath)" of the other element can be placed in the "up (above)" of the other element. Thus, the exemplary term "below" may include both directions of the above follows: Element may also be oriented in different directions, in which case the spatially relative terms are to be interpreted according to the alignment.

As used herein, the term is intended to illustrate the embodiments are not intended to limit the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the text. As used herein, "includes (comprises)" and / or the presence of "(comprising) comprising" is mentioned components, steps, operation and / or device, comprising: one or more other components, operation and / or elements or does not preclude further.

Unless otherwise defined, all terms used herein (including technical and scientific terms) could be used as a means that can be commonly understood by one of ordinary skill in the art to which this invention belongs. Another term that is defined in a general dictionary used are obviously not to be construed as ideal or excessively unless otherwise defined.

Hereinafter, a description will be given of an ultraviolet photodetector according to an embodiment of the present invention will be described with reference to FIG.

1 is a perspective view for explaining an ultraviolet photodetector according to an embodiment of the present invention.

UV photodetector according to an embodiment of the present invention includes a substrate 100, a transparent conductive layer 200, a first bonding layer 300 and the second bonding layer 400.

The substrate 100 may include a transparent material. It may be, for example, substrate 100 is a glass substrate (glass substrate). However, it is not limited to, may be present in various embodiments.

If the thickness of the substrate 100 is too thin, it is difficult in the manufacturing process, and can be surface is too thick, the thickness of the substrate 100, the economic problems. Therefore, the thickness of substrate 100 may be properly adjusted depending on the material.

A transparent conductive layer 200 may be formed on the substrate 100. A transparent conductive layer 200 may be a layer transparent to light is transmitted. A transparent conductive layer 200 also may be a layer conducting electricity through. For example, the transparent conductive layer 200 is FTO (Fluorine doped tin oxide), ITO (Indium-tin-oxide), AZO (Aluminum-zinc-oxide), tin oxide (tin-oxide), indium oxide, Pt, among Au, or IZO (Indium-zinc-oxide) may include at least one.

The upper surface of the transparent conductive layer 200 can be partially exposed. The remaining part of the upper surface of the transparent conductive layer 200 may be covered by a first bonding layer 300 and the second bonding layer 400 to be described later.

On the other hand, the height of the transparent conductive layer 200 is not particularly limited, and may be, for example, 200 nm to 1000 nm range. The electrical conductivity is not satisfied when the height of the transparent conductive layer (200) is less than 200nm. On the contrary, if the height of the transparent conductive layer 200 is not less than 1000 nm, the electrical conductivity is higher, but, the absorption performance of the electrons generated by the photoelectric response can degrade the performance of low ultraviolet photodetector. Further, if the transparent conductive layer 200 is too thick, it is not preferable because it may reduce the effect of reducing the reflectivity.

For a conventional photodetector, by doping the same material but using a PN or PIN junction, a UV photodetector according to the present invention was used as a hetero-junction (heterojunction). When using a doping process, in the manufacture of the photodetector, it can be greater the loss by recombination (recombination) of the carrier. However, in the case of the hetero-junction (heterojunction) without doping process, it can reduce the loss of the carrier. Further, a transparent conductive layer such as FTO electrical conductivity is excellent, because permeability of the light is also excellent is frequently used as a hetero-junction devices.

Within the photodetector substrate 100 and the transparent conductive layer 200, electrons are present in an asymmetric. Within the region of the junction diode in thermal equilibrium the transparent conductive layer 200 and the substrate 100 in a state in which the imbalance in electric charge occurs by diffusion due to concentration gradient of the carrier, thereby forming an electric field (electric field).

Thus, the transparent conductive layer 200 and the substrate 100 into the formed diode region by bonding, the conduction band of the material of the diode region (conduction band) and the valence band (valence band) of the band gap energy (band difference in energy between the when light having energy greater than the gap energy) research, electronic light energy received will be here (excite) in the valence band to the conduction band, the electrons excited in the conduction band will be able to move freely.

Specifically, the transparent conductive layer 200 can be transmitted through the light, non-reflected light can reach the substrate (100). The excited by the light to reach the electrons can easily move in the transparent conductive layer 200 by a difference in the resistivity in the substrate 100.

The first bonding layer 300 may be formed on the transparent conductive layer (200). The first bonding layer 300 may expose a portion of the upper surface of the transparent conductive layer (200). As shown in Figure 1, the first bonding layer 300 is a transparent are formed in a narrower area than the conductive layer (200) covering a portion of the transparent conductive layer 200, thereby exposing the remaining portion.

On the other hand, it limited to any particular height of the first bonding layer 300, but for example, may be in the range 100 nm to 500 nm. First joining without the height of the layer 300 is electrically conductive enough, less than 100nm, it is not preferable because it can reduce the reflectance reduction effect to incident light. In addition, if at least the first engagement height is 500 nm of the layer 300, it is possible to optically reduce the transmission of incident light.

The first bonding layer 300 may include a metal oxide. The first bonding layer 300 may comprise, for example, a ZnO. The first bonding layer 300 may have a first conductivity type. This may be of a different conductivity and the second bonding layer 400 to be described later. It said first conductivity type but may be of N, but is not limited thereto.

The second bonding layer 400 can be formed on the first bonding layer 300. The second bonding layer 400 may cover all of the top surface of the second bonding layer 400. The second bonding layer 400 is a portion of the upper surface of the transparent conductive layer 200 may be exposed. Doedoe Fig. As shown in Figure 1, the second bonding layer 400 is formed in a smaller area than the transparent conductive layer 200 overlaps with a portion of the upper surface of the transparent conductive layer 200, and the remaining portion may not overlap .

On the other hand, the thickness of the second bonding layer 400 may be not particularly limited, but thinner than the thickness of the first bonding layer 300. The second bonding layer 400 can be, for example, 10nm to 300 nm range. Second, the height of the bonding layer 400 can not ensure the conductivity of less than 10nm is not preferable. In addition, if at least the first engagement height is 300 nm of the layer 300, the moving distance of an optical carrier so long can be a collection efficiency greatly lowered.

The second bonding layer 400 may include a metal oxide. The second bonding layer 400 may comprise, for example, the NiO. A second junction layer 400 may have a second conductivity type. This above-mentioned first may be of different conductive junction with layer 300. The second conductive type may be of P is not however, limited.

In this manner, the first bonding layer 300 and the second bonding layer 400 can form a PN junction with a different conductivity type.

In still other certain embodiments of the present invention, the sequence of the first bonding layer 300 and the second bonding layer 400 may vary from each other. That is, the hetero-junction layer may include a first bonding layer 300 and the second bonding layer 400, the hetero-junction layer may be formed on the transparent conductive layer (200). On this time, the transparent conductive layer 200, a first bonding layer 300 and the second bonding layer 400, the second bonding layer (300 in phase may be formed are sequentially stacked, a transparent conductive layer 200 ) and the first bonding layer 400 may be sequentially stacked.

Example 1

It was used as a glass substrate as the substrate. Respectively to form a 500nm and 250nm of the FTO film and the ZnO film on the substrate. Deposited to 50nm Ni film on the composite film of the FTO and ZnO, and the rapid heat-treated (rapid thermal process, RTP). The rapid heat treatment causes a thermal oxide (rapid thermal oxidation) rapidly, 50nm of Ni film was converted to NiO film of 100nm.

Comparative Example 1

Was in the same manner as in Example 1 except that the formation of the FTO film is a single instead of a composite film of FTO and ZnO.

Comparative Example 2

Without forming a composite film of FTO and ZnO, were in the same manner as in Example 1 except that the NiO film formed directly on a glass substrate.

Comparative Example 3

Without forming a composite film of FTO and ZnO, were in the same manner as in Example 1 except that FTO is formed a single film directly on a glass substrate, not formed NiO film.

Experimental Example 1

Example 1, Comparative Example 1 and comparison to grasp the NiO of the crystal structure of Example 2, X-ray diffraction was examined (X-ray diffraction, XRD) pattern.

Figure 2 is illustrating the molecular structure of Example 1, Comparative Examples 1 and 2 of the X-ray diffraction (X-ray diffraction, XRD) is a view showing a pattern is a 3 NiO of the invention of the present invention an isometric drawing of the cubic unit cell for.

Referring to FIG. 2, NiO film 2θ peak occurs at 37.35 °, 43.4 °, 63.06 °, 75.5 °, and 79.55 °. Plane corresponding to the respective peaks (111, 002), (022), the 113 and 222 planes. Referring to Figure 3, an ideal lattice parameters of a NiO is 0.417 nm.

Rapid thermal annealing is effective for Example 1, Comparative Example 1 and Comparative crystalline NiO film formed on Example 2. Figure 1 shows the XRD spectrum corresponding to the Bragg peak (Braggs peaks) of the FTO and ZnO indicated. Each peak corresponds to the hexagonal (hexagonal crystal symmetry) and tetragonal crystal system (tetragonal crystal symmetry).

Figure PCTKR2015013790-appb-T000001

Table 1 is a table showing the Example 1, Comparative Example 1 and Comparative Example 2, the calculated spacing (d-spacing), crystal size (crystalline size, t) and the residual strain (residual strain, Δ) and the like. Example 1 and determination of the FTO and ZnO in Comparative Example 1 because the castle 2θ peak is narrower than that of the comparative example 2 it is possible to improve the crystal structure of NiO. This can be seen as a reduction in the fine NiO film stress (microstrain).

4 is a sectional view taken in AA in Figure 1, Figure 5 is an enlarged view of B part of Fig. In other words, Figure 4 and Figure 5 is a cross-sectional view of the first embodiment.

FIG When 4 and 5, NiO film can be formed without any influence on the interface between the ZnO / FTO film. When the NiO film and the ZnO film and the film surface around the space corresponding to the NiO (111) plane 0.243 nm, a film space corresponding to the ZnO (002) plane 0.262 nm. The interface between the NiO film and the ZnO film can exhibit a heterojunction formed very well without any defect (defect free).

Experimental Example 2

Absorption of the NiO film Comparative Examples 1 to 3 to evaluate the optical properties also were measured for light transmittance and luminescence (photoluminescence, PL).

Figure 6 is a graph for explaining an absorption help permeability according to the Comparative Examples 1 to 3 of the present invention wavelengths, Figure 7 is explaining the absorption coefficient α according to the photon energy of Comparative Example 1 and Comparative Example 2 of the present invention a graph for. Figure 8 is a graph tau (Tauc plot) for comparison of Comparative Examples 1 and 2 of the present invention.

Referring to Figure 6, a comparison of Comparative Examples 1 and form NiO film Example 2 was slightly reduced permeability as compared to Comparative Example 3. However, this reduced permeability has a high correlation in the visible region.

The absorption coefficient (α) is defined by a formula such as Equation 1 below.

Figure PCTKR2015013790-appb-M000001

Here, d is the thickness NiO layer, R is the reflectivity NiO film, T represents a transmittance NiO film. The absorption coefficient (α) is shown as Figure 7 according to the photon energy (E = hν). Where, h is the Planck constant (Planck's constant), ν is a frequency (photon frequency) of the photon.

NiO film in the UV-A region (320-400 nm) has a significantly higher absorption coefficient (α). That is, λ = 400 nm has at a value of α = 3.5 × 10 4 cm -1 , has the α = 3.93 × 10 5 cm -1 values at λ = 310 nm. This indicates that the NiO film absorbs most of light in a transparent UV-A region (320-400 nm) with respect to visible light.

8, a graph can be drawn for tau for calculating the NiO film energy band gap (E g). Figure 8 shows a graph of the E g value of 3.85eV in the Comparative Example 2 of 3.75eV in the E g value and Comparative Example 1. This value is also consistent with the well 3.8eV absorption at 330nm of FIG.

Referring to Figure 9, it can be seen the light luminescence in the NiO film, λ = 355 nm of the laser light source. Figure 9 shows the conduction band and the valence band of the plurality of discharge to inform the existence of the defect position between the peak is confirmed. In the NiO film on the 3.27eV valence band it has the highest defect.

With reference to Fig. 10, illustrates the UV photo-di tekting method according to one embodiment of the present invention.

10 is a view for explaining the method of the ultraviolet-di tekting UV photodetector according to an embodiment of the present invention.

10, the UV photodetector according to an embodiment of the present invention is not required outside the metal electrode. That is, it is possible to de-tekting ultraviolet radiation in contact with the upper surface of the probe 500 without the outer metal electrodes, respectively the second bonding layer 400, the upper surface of the transparent conductive layer 200 of the.

Or In another embodiment of the present invention may be the first bonding layer 300 is formed on the second bonding layer 400. In this case, it is possible to de-tekting ultraviolet radiation in contact with the probe 500 on the upper surface of the second bonding layer 400, an upper surface and a transparent conductive layer 200, respectively.

Outer metal electrode is an optically non-transparent material, so the light is difficult to permeate the ultraviolet photodetector of the present invention according to not use it may have a very excellent visible light-barrier property.

Experimental Example 3

The voltage-current characteristics were measured in the dark current conditions in order to determine the characteristics of the diode UV photodetector according to the first embodiment of the invention.

11 and 12 are views showing a voltage-current curve of the dark current in the condition of the UV photodetector according to an embodiment of the present invention.

11 and 12, a heterojunction device of NiO / ZnO may form a fairly good rectified current. The heterojunction device of NiO / ZnO has a rectification ratio coefficient (consistent rectification ratio (consistent RR) ) of 50 at a low saturation current, such as 0.1μA cm -2. Low saturation current may receive a neat junction formed by the NiO / ZnO interface.

7V or more forward-bias voltage can cause damage to the diode characteristic. As a result, the saturation current 15μA cm -2 RR can be reduced by four. NiO nanocrystals 4.6 × 10 18 N A has a value of cm -3, the neatly formed suppressing the leakage current at the interface of the bonding, and the reverse bias operation can be a function of a good electron blocking.

Experiment 4

To measure the UV photo detection characteristics of NiO / ZnO apparatus of the first embodiment of the present invention was measured photocurrent in the light of 400nm wavelength and intensity 100μWcm -2.

13 to 15] A view to describe a reaction in the reverse bias of a UV photodetector according to an embodiment of the present invention. Specifically, FIGS. 13 to 15 shows the optical response of the reverse bias voltage of -8V to -10V.

In the ultraviolet excitation (UV excitation) state, NiO / ZnO device shows strong photoelectric current of 5.5μA reaction with a slight change in the background current. These results may have the advantage of being able to select the S / N ratio (signal to noise ratio) desired.

Optical response in the measured reverse bias voltage is often much faster than the optical response of the forward bias voltage. This is the result of the capacitance of the space charge becomes lower by a width extended as a reverse bias value is increased. In addition, the power consumption is as low as from 10μW bias operation of -10V.

In order to measure the optical response speed, it is possible to analyze in detail the rising edge and the falling edge in Fig. 14 and 15 shows the rising edge and the falling edge in Fig. 13, respectively.

Rising time (τ r) and falling time (τ f) is defined as the time required for each of the output value of the photo detector changes from 10% of the peak value in the time required for 90% change to 90% to 10%. Rising time (τ r) and falling time (τ f) were measured as 24.2 ms, and 212 ms, respectively. This has the fastest rising time compared to conventional devices. In the detection of the longer wavelength UV slow response time and poor optical response is to solve problems of wide bandgap UV detection device. Thus, a p-NiO / n-ZnO heterojunction structure of the present invention can be a powerful alternative to solve this problem.

16 and 17 is an energy band diagram at the interface between the first and the second bonding layer of a UV photodetector according to an embodiment of the present invention. Specifically, Figure 16 is an energy band diagram in the equilibrium state, Figure 17 is an energy band diagram of the unbalanced state. 16 and 17 are both of the ultraviolet ray-excited state of 400nm.

16 and 17, the level of the donor-type defects (donor type defect) may be located below than 3.15eV conduction band. Once the area of ​​the long wavelength UV is incident, it is absorbed by the free carriers which can be activated in the defect level, and is released from the conduction band. However, due to the low kinetic energy it can not be collected at the back (in contact with the FTO) on the device.

In Referring to Figure 16, the zero bias condition, the generated free electrons by photon are exhausted smoothly within NiO, leaves a very low photocurrent value. Referring to FIG. 17, the other hand, the reverse bias applied by the widened space charge region (SCR) and the lower diffusion capacitance width facilitates the collection efficiency of the free electrons generated by the photons in point contact with FTO.

Further, the nanocrystals The presence of defects in the NiO will greatly enhance the drift transport of carriers, thereby reaching the ZnO layer. These nano-engineered crystal defects in NiO is effective and increases the design possibilities.

Hereinafter, referring to FIGS. 18 to 21, description will now be a UV photodetector manufacturing method according to an embodiment of the present invention. The above description and the overlapping portions are simplified or omitted.

18 to 21 are intermediate view illustrating a UV photodetector manufacturing method according to an embodiment of the present invention.

18, to form a transparent conductive layer 200 on the substrate 100.

The substrate 100 may be an optically transparent material to. For example, the substrate 100 may be a glass substrate. A transparent conductive layer 200 may be also optically transparent material to. For example, the transparent conductive layer 200 is FTO (Fluorine doped tin oxide), ITO (Indium-tin-oxide), AZO (Aluminum-zinc-oxide), tin oxide (tin-oxide), indium oxide, Pt, of Au or IZO (Indium-zinc-oxide) may include at least one.

Then, referring to Figure 19, a first bonding layer 300 on the transparent conductive layer (200).

The first bonding layer 300 is formed in a smaller area than the transparent conductive layer (200) covering a portion of the transparent conductive layer 200, thereby exposing the remaining portion. The first bonding layer 300 may include a metal oxide. The first bonding layer 300 may comprise, for example, the NiO. The first bonding layer 300 may have a first conductivity type. This may be of a different conductivity and the second bonding layer 400 to be described later. The first conductive type may be of P is not however, limited.

Next, Referring to Figure 20, the first metal layer forms a bonding layer (400P) on a (300).

The second bonding layer 400 can be formed on the first bonding layer 300. The second bonding layer 400 may cover all of the top surface of the second bonding layer 400. The second bonding layer 400 is a portion of the upper surface of the transparent conductive layer 200 may be exposed. Doedoe second bonding layer 400 is a transparent are formed in a narrower area than the conductive layer 200 overlaps with a portion of the upper surface of the transparent conductive layer 200, it may not be overlapped with the remaining part.

The second bonding layer 400 may include a metal oxide. The second bonding layer 400 may comprise, for example, a ZnO. A second junction layer 400 may have a second conductivity type. This above-mentioned first may be of different conductive junction with layer 300. The second conductivity type but may be of N, but is not limited thereto.

Then, referring to Figure 21, the rapid metal layer (400P) by thermal oxidation (rapid thermal Oxidation) to form a second bonding layer.

The second bonding layer 400 may include a metal oxide. The second bonding layer 400 may comprise, for example, the NiO. A second junction layer 400 may have a second conductivity type. This above-mentioned first may be of different conductive junction with layer 300. The second conductive type may be of P is not however, limited.

In still other certain embodiments of the present invention, the forming order of the first bonding layer 300 and the second bonding layer 400 may vary from each other. That is, the hetero-junction layer may include a first bonding layer 300 and the second bonding layer 400, the hetero-junction layer may be formed on the transparent conductive layer (200).

At this time, the transparent first bonding layer 300 on the conductive layer 200 is formed first, the second bonding layer 400, a second in-phase may be formed by lamination to the next, a transparent conductive layer 200 the bonding layer 300 is first formed through a heat treatment or the like, then there may be a first bonding layer 400 is formed.

Although it described above experimental examples and embodiments of the invention with reference to the accompanying drawings, one of ordinary skill in the art without changing the departing from the scope and spirit of the invention embodied in other specific forms it will be appreciated that there may be. Thus the embodiments described above are only to be understood as illustrative and non-restrictive in every respect.

Claims (19)

  1. Board;
    A transparent conductive layer formed on the substrate;
    The transparent conductive formed on the layer, the first conductivity type of the first bonding layer and the first bonding layer and a heterojunction (hetero junction) of the first conductivity type different from the second conductivity type forming a second bonding layer UV photodetector comprising a heterojunction layer comprising a.
  2. According to claim 1,
    The first and the second bonding layer is ultraviolet photo detector that exposes a portion of the upper surface of the transparent conductive layer.
  3. According to claim 1,
    It said first junction layer is a UV photodetector comprising a ZnO.
  4. According to claim 1,
    It said second junction layer is a UV photodetector comprising a NiO.
  5. According to claim 1,
    The first conductivity type is N-type,
    The second conductivity type is P type ultraviolet photodetector.
  6. According to claim 1,
    It said first junction layer is formed on the transparent conductive layer,
    Said second junction layer is ultraviolet photo detectors formed on said first junction layer.
  7. According to claim 1,
    It said second junction layer is formed on the transparent conductive layer,
    It said first junction layer is ultraviolet photo detector formed on the second bonding layer.
  8. According to claim 1,
    Ultraviolet photodetector thickness of the transparent conductive layer is 200nm to 800nm.
  9. According to claim 1,
    Wherein the thickness of the first bonding layer is 100 nm to 500 nm ultraviolet photodetector.
  10. According to claim 1,
    Wherein the thickness of the second bonding layer is 10nm to 300 nm ultraviolet photodetector.
  11. According to claim 1,
    The transparent conductive layer is FTO (Fluorine doped tin oxide), ITO (Indium-tin-oxide), AZO (Aluminum-zinc-oxide), tin oxide (tin-oxide), indium oxide, Pt, Au or IZO (Indium- UV photodetector comprising at least one of the zinc-oxide).
  12. 12. The method of claim 11,
    Ultraviolet photodetector the FTO transparent conductive layer.
  13. And forming a transparent conductive layer on a substrate,
    To form a first bonding layer of a first conductivity type on the transparent conductive layer,
    And forming a metal layer on the first bonding layer,
    UV photodetector manufacturing method comprising: forming a second bonding layer by thermal oxidation (rapid thermal Oxidation) rapidly to the metal layer.
  14. 14. The method of claim 13,
    It said first junction layer is ultraviolet photo detector manufacturing method comprising the ZnO.
  15. 14. The method of claim 13,
    The second metal layer contains Ni,
    The second bonding layer is prepared UV photodetector comprising a NiO.
  16. 14. The method of claim 13,
    The first conductivity type is N-type,
    The second conductivity type is P-type method for producing ultraviolet photodetector.
  17. 14. The method of claim 13,
    It said second junction layer is a UV photodetector manufacturing method different from the first type and the second conductivity of the first conductivity type.
  18. Substrate and a transparent conductive layer formed on the substrate and the first conductive first bonding layer of the type formed on the transparent conductive layer, wherein the first bonding layer and the hetero-junction on the first bonding layer (hetero junction ) to achieve provide ultraviolet photodetector, including a second bonding layer of the other second conductivity type and first conductivity type, and
    Incident ultraviolet light to the ultraviolet photodetector, and
    UV photo-di tekting method comprising contacting a first probe directly on the upper surface of the transparent conductive layer, in contact with the second probe directly on the upper surface of the second bonding layer detects the ultraviolet light.
  19. 19. The method of claim 18,
    A UV photo-di tekting how the wavelength of the ultraviolet ray is 320 to 400 nm.
PCT/KR2015/013790 2015-09-09 2015-12-16 Ultraviolet photodetector and method for manufacturing same WO2017043704A1 (en)

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