Substrate with transparent conductive oxide film, process for its production and photoelectric conversion element

• US 20050000564A1
• Filed: 04/19/2004
• Published: 01/06/2005
• Est. Priority Date: 10/19/2001
• Status: Active Grant

• Current Assignee: AGC, Inc.
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Kambe, Mika, Fukawa, Makoto, Taneda, Naoki, Sato, Kazuo, Aomine, Nobutaka
• Granted Patent: US 7,179,527 B2
• Time in Patent Office: Days
• US Class Current: 136/256
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/04 Coating on selected surface areas, e.g. using masks
• CPC Class Codes: C23C 16/407 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: H01L 31/022466 made of transparent conductive layers, e.g. TCO, ITO layers
• CPC Class Codes: H01L 31/022483 composed of zinc oxide [ZnO]
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/02366 of the substrate or of a layer on the substrate, e.g. textured ITO/glass substrate or superstrate, textured polymer layer on glass substrate
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10T 428/24364 with transparent or protective coating
• CPC Class Codes: Y10T 428/261 In terms of molecular thickness or light wave length
• CPC Class Codes: Y10T 428/263 Coating layer not in excess of 5 mils thick or equivalent
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A substrate with a transparent conductive oxide film (especially a substrate with a transparent conductive oxide film useful as a substrate for a thin-film silicon-based solar cell) being excellent in mass production efficiency and being characterized by having a low resistance, a high transparency and a good light scattering performance over a full wavelength region (300 nm to 3 μm) of solar ray, a process for its production, and a photoelectric conversion element (especially, solar cell) employing the substrate, are presented. A substrate with a transparent conductive oxide film, comprising a substrate and a transparent conductive oxide layer formed on the substrate and constituted by a plurality of ridges is and a plurality of flat portions, wherein the surfaces of the ridges and the flat portions, have many continuous micron-size protrusions.

Claims

1. A substrate with a transparent conductive oxide film, comprising a substrate and a transparent conductive oxide film provided on the substrate and constituted by a plurality of ridges and a plurality of flat portions, wherein the surfaces of the ridges and the flat portions have many continuous micron-size protrusions.

2. The substrate with a transparent conductive oxide film according to claim 1, wherein the protrusions have basal plane diameters of from 0.1 to 0.3 μ

m and height/basal plane diameter ratios of from 0.7 to 1.2.

6. The substrate with a transparent conductive oxide film according to claim 1, wherein the substrate with the transparent conductive oxide film, has a sheet resistance of from 8 to 20 Ω

/□ and

an optical transmittance of from 80 to 90% at 550 nm measured by an immersion liquid method.

13. The substrate with a transparent conductive oxide film according to claim 1, wherein the substrate with the transparent conductive oxide film, has a haze of from 10 to 95% over a full wavelength region of from 400 to 800 nm.

14. A process for producing the substrate with the transparent conductive oxide film as defined in claim 1, which comprises forming, on a transparent substrate, discontinuous small ridges made of a first oxide by an atmospheric pressure CVD method, and forming thereon a continuous layer made of a second oxide.

15. The process for producing the substrate with the transparent conductive oxide film according to claim 14, wherein the small ridges are formed by an atmospheric pressure CVD method employing tin tetrachloride, water and hydrogen chloride.

16. The process for producing the substrate with the transparent conductive oxide film according to claim 14, wherein the continuous layer made of the second oxide is formed on the discontinuous small ridges made of the first oxide, by an atmospheric pressure CVD method.

17. The process for producing the substrate with the transparent conductive oxide film according to claim 16, wherein a film made of an oxide different in the composition from the first and second oxides, is formed between the discontinuous small ridges made of the first oxide and the continuous layer made of the second oxide, by an atmospheric pressure CVD method.

18. A photoelectric conversion element having a rear face electrode, via a photoelectric conversion layer, on the substrate with the transparent conductive oxide film as defined in any one of claims 1 to 13.

19. The photoelectric conversion element according to claim 18, wherein the photoelectric conversion layer is a layer having p-, i- and n-type-layers formed in this order.

20. The photoelectric conversion element according to claim 18, wherein the rear face electrode is a metal film containing Ag in an amount of at least 95 mol % in the film.

21. The photoelectric conversion element according to claim 20, wherein the metal film contains Pd or Au in an amount of from 0.3 to 5 mol % in the film.

22. The photoelectric conversion element according to claim 18, which has a contact-improving layer between the rear face electrode and the n-type-layer nearest to the rear face electrode, between the photoelectric conversion layer and the rear face electrode.

23. The photoelectric conversion element according to claim 22, wherein the contact-improving layer has a resistivity of not more than 1×

10<sup>−

2</sup> Ω

·

cm.

24. The photoelectric conversion element according to claim 22, wherein the contact-improving layer has an absorption coefficient of not more than 5×

10³ cm<sup>−

1</sup> in a wavelength region of from 500 to 800 nm.

25. The photoelectric conversion element according to claim 22, wherein the contact-improving layer contains zinc oxide (ZnO) as the main component, and at least 90 atomic % of the total metal component in the layer is Zn.

26. The photoelectric conversion element according to claim 25, wherein the layer containing ZnO as the main component, contains Ga or Al in an amount of from 0.3 to 10 mol % based on the summation with Zn.

3. A substrate with a transparent conductive oxide film, comprising a substrate and a transparent conductive oxide film provided on the substrate, wherein the substrate with the transparent conductive oxide film, has a haze of from 10 to 95% over a full wavelength region of from 400 to 800 nm, and the difference of the absolute values between the maximum value and the minimum value of the haze (the maximum value−

the minimum value) is not more than 50%.

4. The substrate with a transparent conductive oxide film according to claim 3, wherein the substrate with the transparent conductive oxide film, has a haze of from 40 to 70% (as an average of from 400 to 600 nm) in a wavelength region of from 400 to 600 nm and a haze of from 20 to 40% (as an average of from 600 to 800 nm) in a wavelength region of from 600 to 800 nm.

5. A substrate with a transparent conductive oxide film, comprising a substrate and a transparent conductive oxide film provided on the substrate, wherein the transparent conductive oxide film comprises discontinuous small ridges made of a first oxide and a continuous layer made of a second oxide, formed on the small ridges, wherein the surface of the continuous layer has many continuous micron-size protrusions.

7. The substrate with a transparent conductive oxide film according to claim 5, wherein the small ridges have basal plane diameters of from 0.2 to 2.0 μ

m.

8. The substrate with a transparent conductive oxide film according to claim 5, wherein the first oxide is composed of SnO₂ or SnO₂ containing fluorine, the fluorine content being not more than 0.01 mol % based on SnO₂.

9. The substrate with a transparent conductive oxide film according to claim 5, wherein the second oxide is a transparent conductive oxide containing at least one member selected from the group consisting of SnO₂, ZnO and In₂O₃.

10. The substrate with a transparent conductive oxide film according to claim 5, wherein the second oxide is SnO₂ containing fluorine-doped tin as the main component, contains fluorine in an amount of from 0.01 to 4 mol % based on SnO₂ and has a conductive electron density of from 5×

10¹⁹ to 4×

10²⁰ cm<sup>−

3</sup>.

11. The substrate with a transparent conductive oxide film according to claim 5, wherein a film made of an oxide different in the composition from the first and second oxides, is formed between the discontinuous small ridges made of the first oxide and the continuous layer made of the second oxide.

12. The substrate with a transparent conductive oxide film according to claim 11, wherein the first oxide is SnO₂, the different oxide is SiO₂, and the second oxide is fluorine-doped SnO₂.