Photovoltaic device including a p-n junction and method of manufacturing

Patent metadata

Field	Value
Publication number	US-10243092-B2
Application number	US-201715612078-A
Country	US
Kind code	B2
Filing date	Jun 2, 2017
Priority date	Feb 1, 2013
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A photovoltaic device includes a substrate structure and a p-type semiconductor absorber layer, the substrate structure including a CdSSe layer. A photovoltaic device may alternatively include a CdSeTe layer. A process for manufacturing a photovoltaic device includes forming a CdSSe 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 a p-type absorber layer above the CdSSe layer.

First claim

What is claimed:

1. A photovoltaic structure, comprising:
a substrate structure comprising a transparent conductive oxide (TCO) layer, a buffer layer, and a barrier layer;
an absorber layer formed over the substrate structure, wherein:
a p-n junction is formed between the absorber layer and the substrate structure,
the absorber layer consists of a p-type cadmium selenide telluride layer,
the p-type cadmium selenide telluride layer is composed of a CdSe x Te 1-x compound,
the p-type cadmium selenide telluride layer has a gradient of selenium to tellurium ratio such that x varies in value through a thickness of the p-type cadmium selenide telluride layer, and
the p-type cadmium selenide telluride layer has higher selenium concentration adjacent to the substrate structure and decreasing through a thickness of the absorber layer.

2. The photovoltaic structure of claim 1 , wherein x of the p-type cadmium selenide telluride layer is in a range of about 0.01 to about 0.25.

3. The photovoltaic structure of claim 1 , wherein x of the p-type cadmium selenide telluride layer is in a range of about 0.05 to about 0.20.

4. The photovoltaic structure of claim 1 , wherein x varies continuously through the thickness of the p-type cadmium selenide telluride layer.

5. The photovoltaic structure of claim 1 , wherein the p-type cadmium selenide telluride layer is between about 2000 nm to about 4000 nm thick.

6. The photovoltaic structure of claim 4 , wherein the p-type cadmium selenide telluride layer is between about 2500 nm to about 3500 nm thick.

7. The photovoltaic structure of claim 1 , wherein the TCO layer comprises tin oxide, zinc oxide, cadmium stannate, or doped variations thereof.

8. The photovoltaic structure of claim 1 , wherein the TCO layer comprises n-type material and forms the p-n junction with the p-type cadmium selenide telluride layer.

9. The photovoltaic structure of claim 1 , wherein the p-type cadmium selenide telluride layer comprises a dopant.

10. A method for forming a photovoltaic structure, comprising:
providing a substrate structure comprising a transparent conductive oxide (TCO) layer, a buffer layer, and a barrier layer;
depositing a CdSe layer over the substrate structure;
depositing a CdTe layer over the CdSe layer; and
alloying the CdSe layer and the CdTe layer whereby an absorber layer is formed over the substrate structure, wherein:
the absorber layer consists of a p-type cadmium selenide telluride layer,
the p-type cadmium selenide telluride layer is composed of a CdSe x Te 1-x compound, and

the p-type cadmium selenide telluride layer has a gradient of selenium to tellurium ratio such that x varies in value through a thickness of the cadmium selenide telluride layer.

11. The method of claim 10 , comprising depositing a CdSeTe layer over the CdTe layer.

12. The method of claim 11 , wherein the CdSeTe layer is deposited from a co-evaporation of a blended mixture of CdSe and CdTe powder.

13. The method of claim 11 , wherein the CdSeTe layer is deposited from the evaporation of a pre-alloyed CdSeTe powder.

14. The method of claim 10 , comprising activating the absorber layer with a chlorine-doping material.

15. The method of claim 10 , wherein the CdSe layer and the CdTe layer are alloyed using an anneal or a heat treatment process.

16. A method for forming a photovoltaic structure, comprising:
providing a substrate structure comprising a transparent conductive oxide (TCO) layer, a buffer layer, and a barrier layer;
depositing a CdSeTe layer over the substrate structure whereby an absorber layer is formed over the substrate structure, wherein:
a p-n junction is formed between the absorber layer and the substrate structure,
the absorber layer consists of a p-type cadmium selenide telluride layer,
the p-type cadmium selenide telluride layer is composed of a CdSe x Te 1-x compound, and
the p-type cadmium selenide telluride layer has a gradient of selenium to tellurium ratio such that x varies in value through a thickness of the cadmium selenide telluride layer, and
the p-type cadmium selenide telluride layer has higher selenium concentration adjacent to the substrate structure and decreasing through a thickness of the absorber layer.

17. The photovoltaic structure of claim 1 , wherein the photovoltaic structure does not have a CdS window layer.

18. The photovoltaic structure of claim 1 , further comprising a back contact layer over the absorber layer, wherein the back contact layer comprises: silver, nickel, copper, aluminum, titanium, palladium, chrome, molybdenum, gold, or combinations thereof.

Assignees

• First Solar Inc

Inventors

• Damjanovic Dan
• Liao Feng
• Powell Rick
• Shao Rui
• Trivedi Jigish
• Zhao Zhibo

Classifications

• Y02E10/543

  Solar cells from Group II-VI materials · CPC title

• H01L31/1864

  Electricity · mapped topic

• H01L31/02966 Primary

  Electricity · mapped topic

• H01L31/073

  Electricity · mapped topic

• Y02P70/521

  Cross-Sectional Technologies · mapped topic