Photovoltaic device including a back contact and method of manufacturing

Patent metadata

Field	Value
Publication number	US-9269849-B2
Application number	US-201414221245-A
Country	US
Kind code	B2
Filing date	Mar 20, 2014
Priority date	Mar 22, 2013
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

A photovoltaic device includes a substrate, a transparent conductive oxide, an n-type window layer, a p-type absorber layer and an electron reflector layer. The electron reflector layer may include zinc telluride doped with copper telluride, zinc telluride alloyed with copper telluride, or a bilayer of multiple layers containing zinc, copper, cadmium and tellurium in various compositions. A process for manufacturing a photovoltaic device includes forming a layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process includes forming an electron reflector layer over a p-type absorber layer.

First claim

What is claimed:

1. A photovoltaic device comprising:
a substrate structure including a base layer, a transparent conductive oxide layer, at least one semiconductor layer; and an electron reflector layer disposed over the substrate structure, wherein the electron reflector layer comprises zinc telluride doped with copper telluride.

2. The photovoltaic device of claim 1 , wherein the zinc telluride is doped with copper telluride at a concentration between 0.01% and 5%.

3. The photovoltaic device of claim 1 , wherein the zinc telluride is doped with copper telluride at a concentration between 2% and 5%.

4. The A photovoltaic device of comprising:
a substrate structure including a base layer, a transparent conductive oxide layer, at least one semiconductor layer; and an electron reflector layer disposed over the substrate structure, wherein the electron reflector layer comprises (Cu 2 ) x Zn (1-x) Te, where x is between 20% and 35%.

5. A photovoltaic device of claim 1 , comprising:
a substrate structure including a base layer, a transparent conductive oxide layer, at least one semiconductor layer; and an electron reflector layer disposed over the substrate structure, wherein the electron reflector layer comprises a bilayer of two sublayers wherein a first sublayer material is chosen from: zinc telluride doped with copper telluride, and zinc telluride-copper telluride alloy; and where the second sublayer material is chosen from: zinc telluride doped with elemental copper, zinc telluride, cadmium zinc telluride, and copper telluride.

6. The photovoltaic device of claim 5 , wherein the first sublayer is zinc telluride doped with copper telluride at a concentration of between 0.01% and 5%; and where the second sublayer is zinc telluride.

7. The photovoltaic device of claim 5 , wherein the first sublayer is zinc telluride alloyed with copper telluride at a concentration of between 5% and 60%; and where the second sublayer is cadmium zinc telluride.

8. The photovoltaic device of claim 1 , wherein the amount of copper telluride dopant in the electron reflector layer increases in a gradient with distance from the semiconductor layer.

9. The photovoltaic device of claim 4 , wherein the amount of Cu 2 Te in the (Cu 2 ) x Zn (1-x) Te alloy in the electron reflector layer increases in a gradient with distance from the semiconductor layer.

10. The photovoltaic device of claim 1 , further comprising an additional electron reflector sublayer comprising cadmium zinc telluride (CZT).

11. The photovoltaic device of claim 4 , further comprising an additional electron reflector sublayer comprising zinc telluride (ZnTe).

12. A process for manufacturing the photovoltaic device of claim 1 , comprising forming the electron reflector layer on the substrate structure by depositing a zinc telluride doped with copper telluride at a concentration of between 0.01% and 5% by one of: (a) a vapor deposition process; or (b) a sputtering process.

13. A process for manufacturing the photovoltaic device of claim 4 , comprising forming the electron reflector layer on the substrate structure by depositing a zinc telluride alloyed with copper telluride at a concentration of between 20% and 35% by one of: (a) a vapor deposition process; or (b) a sputtering process.

14. A process for manufacturing the photovoltaic device of claim 5 , comprising forming the electron reflector layer on the substrate structure by sequentially forming a first sublayer and a second sublayer, wherein forming at least one sublayer is done by one of: (a) a vapor deposition process; or (b) a sputtering process.

15. The process of claim 14 , wherein forming at least one of the first sublayer and the second sublayer is performed by depositing a zinc telluride doped with copper telluride at a concentration of between 0.01% and 5%.

16. The process of claim 14 , wherein forming at least one of the first sublayer and the second sublayer is performed by depositing a zinc telluride alloyed with copper telluride at a concentration of between 5% and 60%.

Assignees

• First Solar Inc

Inventors

• Yu San
• Palaniappagounder Veluchamy
• Addepalli Pratima
• Khan Imran

Classifications

• H10F77/311

  for photovoltaic cells · CPC title

• H10F77/244

  made of transparent conductive layers, e.g. transparent conductive oxide [TCO] layers · CPC title

• H10F77/211

  for photovoltaic cells · CPC title

• H10F71/138

  Manufacture of transparent electrodes, e.g. transparent conductive oxides [TCO] or indium tin oxide [ITO] electrodes · CPC title

• H10F71/128

  Annealing · CPC title