Photovoltaic devices and semiconductor layers with group v dopants and methods for forming the same

Patent metadata

Field	Value
Publication number	US-12356755-B2
Application number	US-202217986747-A
Country	US
Kind code	B2
Filing date	Nov 14, 2022
Priority date	Dec 7, 2017
Publication date	Jul 8, 2025
Grant date	Jul 8, 2025

Abstract

According to the embodiments provided herein, a photovoltaic device can include an absorber layer. The absorber layer can be doped p-type with a Group V dopant and can have a carrier concentration of the Group V dopant greater than 4×1015 cm−3. The absorber layer can include oxygen in a central region of the absorber layer. The absorber layer can include an alkali metal in the central region of the absorber layer. Methods for carrier activation can include exposing an absorber layer to an annealing compound in a reducing environment. The annealing compound can include cadmium chloride and an alkali metal chloride.

First claim

What is claimed is:

1. A photovoltaic device comprising an absorber layer, wherein:
the absorber layer comprises cadmium, tellurium, and selenium;
the absorber layer is doped p-type with a Group V dopant and has a carrier concentration of the Group V dopant greater than 4×10 15 cm −3 ;
the absorber layer comprises oxygen in a central region of the absorber layer;
the absorber layer comprises an alkali metal in the central region of the absorber layer;
a ratio of an atomic concentration of the alkali metal to an atomic concentration of the oxygen is at least 0.1 in the central region of the absorber layer; and
the central region is the middle 50% of the absorber layer, which is offset by 25% of the thickness of the absorber layer from each of a first surface and a second surface of the absorber layer.

2. The photovoltaic device of claim 1 , wherein the alkali metal is potassium.

3. The photovoltaic device of claim 1 , wherein the alkali metal is rubidium.

4. The photovoltaic device of claim 1 , wherein the carrier concentration of the Group V dopant is between 8×10 15 cm −3 and 6×10 16 cm −3 .

5. The photovoltaic device of claim 4 , wherein an atomic concentration of the Group V dopant in the central region of the absorber layer is greater than 1×10 17 cm −3 .

6. The photovoltaic device of claim 1 , comprising a transparent conductive oxide layer disposed between the absorber layer and an energy side of the photovoltaic device, wherein the transparent conductive oxide layer comprises the alkali metal.

7. The photovoltaic device of claim 6 , wherein an atomic concentration of the alkali metal in the transparent conductive oxide layer is greater than the atomic concentration of the alkali metal in the central region of the absorber layer.

8. The photovoltaic device of claim 7 , wherein an alkali metal ratio of the atomic concentration of the alkali metal in the transparent conductive oxide layer to the atomic concentration of the alkali metal in the central region of the absorber layer is less than 1,000.

9. The photovoltaic device of claim 7 , wherein an alkali metal ratio of the atomic concentration of the alkali metal in the transparent conductive oxide layer to the atomic concentration of the alkali metal in the central region of the absorber layer is less than 500.

10. The photovoltaic device of claim 7 , wherein an alkali metal ratio of the atomic concentration of the alkali metal in the transparent conductive oxide layer to the atomic concentration of the alkali metal in the central region of the absorber layer is less than 100.

11. The photovoltaic device of claim 1 , wherein the Group V dopant is arsenic.

12. The photovoltaic device of claim 1 , wherein an atomic concentration of the Group V dopant in the central region of the absorber layer is between about 5×10 16 cm −3 and about 1×10 19 cm −3 .

13. The photovoltaic device of claim 1 , wherein the alkali metal comprises rubidium and potassium.

14. The photovoltaic device of claim 1 , wherein the alkali metal comprises lithium.

15. The photovoltaic device of claim 1 , wherein the Group V dopant comprises nitrogen, phosphorous, arsenic, antimony, bismuth, or a combination thereof.

16. The photovoltaic device of claim 1 , wherein the ratio of the atomic concentration of the alkali metal to the atomic concentration of the oxygen is at least 0.75 in the central region of the absorber layer.

17. A photovoltaic device comprising an absorber layer, wherein:
the absorber layer comprises cadmium, tellurium, and selenium;
the absorber layer is p-type;
the absorber layer is doped with a Group V dopant;
the Group V dopant comprises at least one of: phosphorous, arsenic, antimony, or bismuth;
an atomic concentration of the Group V dopant in a central region of the absorber layer is between about 3×10 17 cm −3 and about 1×10 19 cm −3 ;

the absorber layer has a carrier concentration between 8×10 15 cm −3 and 6×10 16 cm −3 ;
the absorber layer comprises an alkali metal in the absorber layer, wherein an atomic concentration of the alkali metal is between about 2×10 16 cm −3 and about 1×10 19 cm −3 in the absorber layer;
the central region is the middle 50% of the absorber layer, which is offset by 25% of the thickness of the absorber layer from each of a first surface and a second surface of the absorber layer; and
the alkali metal comprises at least one of potassium (K) or rubidium (Rb), wherein:
the absorber layer comprises oxygen in the central region of the absorber layer; and
an alkali metal to oxygen ratio is between about 0.1 and about 1,000 in the central region of the absorber layer.

Assignees

• First Solar Inc

Inventors

• Cao Hongbo
• Grover Sachit
• Huber William Hullinger
• Li Xiaoping
• Lu Dingyuan
• Malik Roger
• Peng Hongying
• Shiang Joseph John
• Xin Qianqian
• Xiong Gang

Classifications

• H10F77/1237

  having at least three elements, e.g. HgCdTe · CPC title

• H10F71/1253

  comprising at least three elements, e.g. HgCdTe · CPC title

• H10F71/128

  Annealing · CPC title

• H10F10/162

  comprising only Group II-VI materials, e.g. CdS/CdTe photovoltaic cells · CPC title

• H10F71/131

  Recrystallisation; Crystallization of amorphous or microcrystalline semiconductors · CPC title