# US 8,785,232 B2 · Photovoltaic device

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- Number: US 8,785,232 B2
- Document ID: US8785232B2
- Status: Granted
- Kind: B2
- Application number: 13/945,583
- Filed: 2013-07-18
- Published: 2013-11-14
- Granted: 2014-07-22
- Earliest claimed: 2009-05-12
- Assignees: First Solar, Inc.
- Applicants: First Solar, Inc.
- Inventors: Gang Xiong; Rick C. Powell; Aaron Roggelin; Kuntal Kumar; Arnold Allenic; Kenneth M. Ring; Charles E. Wickersham
- Web page: https://patentgrep.com/patent/US8785232B2

## CPC

- H10F 77/1233: {characterised by the dopants}
- H10F 10/162: comprising only Group II-VI materials, e.g. CdS/CdTe photovoltaic cells
- Y02E 10/543: Solar cells from Group II-VI materials
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method to improve CdTe-based photovoltaic device efficiency is disclosed. The CdTe-based photovoltaic device can include oxygen or silicon in semiconductor layers.

## Claims

### Claim 1

A photovoltaic device comprising:
a transparent conductive oxide layer;
a semiconductor bi-layer adjacent to the transparent conductive oxide layer, wherein the semiconductor bi-layer comprises a semiconductor absorber layer and a semiconductor window layer and one or more of the semiconductor window layer and the semiconductor absorber layer comprises a carrier concentration modifier comprising silicon; and
a back contact layer adjacent to the semiconductor bi-layer.

### Claim 2 (depends on 1)

The photovoltaic device of claim 1, wherein the semiconductor absorber layer comprises decreased carrier concentration.

### Claim 3 (depends on 1)

The photovoltaic device of claim 1, wherein the semiconductor absorber layer comprises material comprising silicon.

### Claim 4 (depends on 1)

The photovoltaic device of claim 1, wherein the semiconductor window layer and semiconductor absorber layer comprise material comprising oxygen.

### Claim 5 (depends on 1)

The photovoltaic device of claim 1, wherein the semiconductor absorber layer comprises material comprising oxygen.

### Claim 6 (depends on 1)

The photovoltaic device of claim 1, wherein one or more of the semiconductor absorber layer and the semiconductor window layer comprises a II-VI semiconductor.

### Claim 7 (depends on 1)

The photovoltaic device of claim 1, wherein the semiconductor window layer comprises cadmium sulfide (CdS).

### Claim 8 (depends on 1)

The photovoltaic device of claim 1, wherein the semiconductor absorber layer comprises cadmium telluride (CdTe).

### Claim 9 (depends on 1)

The photovoltaic device of claim 1, wherein the semiconductor window layer comprises increased carrier concentration.

### Claim 10 (depends on 1)

The photovoltaic device of claim 1, wherein the semiconductor absorber layer and the semiconductor window layer comprises silicon.

### Claim 11 (depends on 1)

The photovoltaic device of claim 1, further comprising an additional layer comprising silicon, and wherein the silicon of the additional layer can diffuse into the semiconductor absorber layer and semiconductor window layer.

### Claim 12 (depends on 1)

The photovoltaic device of claim 1, wherein the transparent conductive oxide layer comprises silicon, and wherein the silicon of the transparent conductive oxide layer can diffuse into the semiconductor absorber layer and semiconductor window layer.

### Claim 13 (depends on 1)

The photovoltaic device of claim 1, wherein the back contact layer comprises silicon, and wherein the silicon of the back contact layer can diffuse into the semiconductor absorber layer and semiconductor window layer.