# US 10,319,873 B2 · Photovoltaic devices including doped semiconductor films

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- Number: US 10,319,873 B2
- Document ID: US10319873B2
- Status: Granted
- Kind: B2
- Application number: 14/994,830
- Filed: 2016-01-13
- Published: 2016-05-05
- Granted: 2019-06-11
- Earliest claimed: 2007-11-02
- Assignees: First Solar, Inc.
- Applicants: First Solar, Inc.
- Inventors: Rick C. Powell; Upali Jayamaha; Anke Abken; Markus Gloeckler; Akhlesh Gupta; Roger T. Green; Peter Meyers
- Web page: https://patentgrep.com/patent/US10319873B2

## CPC

- H10F 71/125: {The active layers comprising only Group II-VI materials, e.g. CdS, ZnS or CdTe}
- H10F 10/162: comprising only Group II-VI materials, e.g. CdS/CdTe photovoltaic cells
- H10F 71/1253: {comprising at least three elements, e.g. HgCdTe}
- H10F 71/128: {Annealing}
- H10F 77/1233: {characterised by the dopants}
- H10F 77/1237: {having at least three elements, e.g. HgCdTe}
- H10F 77/1243: {characterised by the dopants}
- H10F 71/129: {Passivating}
- H10F 71/138: {Manufacture of transparent electrodes, e.g. transparent conductive oxides [TCO] or indium tin oxide [ITO] electrodes}
- H10F 77/244: {made of transparent conductive layers, e.g. transparent conductive oxide [TCO] layers}
- Y02E 10/50: Photovoltaic [PV] energy
- Y02E 10/543: Solar cells from Group II-VI materials
- Y02E 10/544: Solar cells from Group III-V 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 photovoltaic cell can include a dopant in contact with a semiconductor layer.

## Claims

### Claim 1

A method for forming an absorber layer of a photovoltaic cell comprising:
vaporizing a source material to form a semiconductor vapor with a vapor transport deposition system having a distributor;
distributing the semiconductor vapor via the distributor to a deposition chamber, wherein the semiconductor vapor comprises Cd and Te;
applying excess Cd or Te to the semiconductor vapor, whereby:
the vapor is off-stoichiometric compared to CdTe, and
a vapor phase overpressure of Cd or Te is introduced to the semiconductor vapor;
controlling vacancy concentration in the absorber layer using the vapor phase overpressure; and
introducing a P-type dopant into the absorber layer at a concentration greater than 0.5 ppma.

### Claim 2 (depends on 1)

The method of claim 1, wherein the P-type dopant is introduced by diffusion.

### Claim 3 (depends on 1)

The method of claim 1, wherein the P-type dopant is introduced by a vapor.

### Claim 4 (depends on 3)

The method of claim 3, wherein the P-type dopant comprises P, As, Sb, Na, K, or Rb.

### Claim 5 (depends on 1)

The method of claim 1, wherein the P-type dopant is introduced as a mixed powder.

### Claim 6 (depends on 1)

The method of claim 1, wherein the P-type dopant is introduced as a solid powder.

### Claim 7 (depends on 1)

The method of claim 1, wherein the P-type dopant is introduced throughout the absorber layer.

### Claim 8 (depends on 1)

The method of claim 1, wherein the P-type dopant is added to a portion of the absorber layer.

### Claim 9 (depends on 1)

The method of claim 1, wherein the P-type dopant is introduced during heat treatment.

### Claim 10 (depends on 9)

The method of claim 9, wherein the heat treatment temperature is about 400 degrees Celsius.

### Claim 11 (depends on 9)

The method of claim 9, wherein the P-type dopant is applied to a surface of the absorber layer prior to heat treatment.

### Claim 12 (depends on 9)

The method of claim 9, comprising applying a flux solution to a surface of the absorber layer prior to heat treatment, wherein the flux solution comprises CdCl2.

### Claim 13 (depends on 12)

The method of claim 12, comprising adding Group I and Group V species to the flux solution.

### Claim 14 (depends on 1)

The method of claim 1, wherein the source material comprises a CdTe source powder and excess Cd powder or Te powder.

### Claim 15 (depends on 1)

The method of claim 1, wherein the source material comprises a two-phase powder blend.

### Claim 16 (depends on 1)

The method of claim 1, wherein the source material comprises an off-stoichiometric source material.

### Claim 17 (depends on 1)

The method of claim 1, wherein the P-type dopant comprises N, P, As, Sb, or Bi.

### Claim 18 (depends on 1)

The method of claim 1, wherein the P-type dopant comprises Li, Na, K, Rb, Cs, Cu, Ag, or Au.

### Claim 19 (depends on 1)

The method of claim 1, wherein the absorber layer comprises a mixture of CdTe and at least one semiconductor selected from the group consisting of ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, MgO, MgS, MgSe, MgTe, HgO, HgS, HgSe, HgTe, MnO, MnS, MnTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, TlN, TlP, TlAs, and TlSb.

### Claim 20

A method for forming an absorber layer of a photovoltaic cell comprising:
depositing the absorber layer, wherein the absorber layer comprises a mixture of CdTe and at least one semiconductor selected from the group consisting of ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, MgO, MgS, MgSe, MgTe, HgO, HgS, HgSe, HgTe, MnO, MnS, MnTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, TlN, TlP, TlAs, and TlSb;
applying a flux solution to a surface of the absorber layer, wherein the flux solution comprises CdCl2 and a chloride compound, and wherein the chloride compound comprises a Group I element, a Group V element, or both;
heat treating the absorber layer with the flux solution; and
introducing a P-type dopant into the absorber layer at a concentration greater than 0.5 ppma.