Methods for group V doping of photovoltaic devices

Patent metadata

Field	Value
Publication number	US-11201257-B2
Application number	US-201916966424-A
Country	US
Kind code	B2
Filing date	Jan 14, 2019
Priority date	Feb 1, 2018
Publication date	Dec 14, 2021
Grant date	Dec 14, 2021

Abstract

According to the embodiments provided herein, a method for doping an absorber layer can include contacting the absorber layer with an annealing compound. The annealing compound can include cadmium chloride and a group V salt comprising an anion and a cation. The anion, the cation, or both can include a group V element. The method can include annealing the absorber layer, whereby the absorber layer is doped with at least a portion of the group V element of the annealing compound.

First claim

What is claimed is:

1. A method for doping an absorber layer, comprising:
contacting the absorber layer with an annealing compound, wherein:
the absorber layer comprises cadmium, and tellurium;
the annealing compound comprises cadmium chloride and a group V salt comprising an anion and a cation;
the anion, the cation, or both comprise a group V element;
a ratio of cadmium chloride to group V salt within the annealing compound, on a weight per volume basis, is at least 30 to 1; and

annealing the absorber layer, whereby the absorber layer is doped with at least a portion of the group V element of the annealing compound.

2. The method of claim 1 , wherein the annealing compound is a solution, and a proportion of the group V salt to a total amount of the annealing compound is less than 100 grams per liter.

3. The method of claim 2 , wherein the proportion of the group V salt to the total amount of the annealing compound is between 1/25 grams per liter and 20 grams per liter.

4. The method of claim 1 , wherein a grain size of the absorber layer is increased during annealing of the absorber layer.

5. The method of claim 1 , wherein the group V salt is ammonium dihydrogen arsenate.

6. The method of claim 1 , wherein the group V salt is diammonium hydrogen phosphate.

7. The method of claim 1 , wherein the group V element is nitrogen.

8. The method of claim 1 , wherein the group V element is phosphorous.

9. The method of claim 1 , wherein the group V element is arsenic.

10. The method of claim 1 , wherein the group V element is antimony.

11. The method of claim 1 , wherein the group V element is bismuth.

12. The method of claim 1 , comprising exposing an absorber layer to a reducing environment, while the absorber layer is annealed.

13. The method of claim 12 , wherein the reducing environment comprises a forming gas configured to mitigate formation of group V oxides, the forming gas comprising hydrogen, nitrogen, carbon, or combinations thereof.

14. The method of claim 1 , wherein the absorber layer is annealed at a temperature between 350° C. and 500° C. for between 5 minutes and 60 minutes.

15. The method of claim 1 , wherein:
the annealing compound comprises an alkali metal chloride; and
at least a portion of the group V dopant is activated during annealing of the absorber layer.

16. The method of claim 1 , wherein, after the absorber layer is annealed, an atomic concentration of the group V dopant in a central region of the absorber layer is greater than 1×10 16 cm −3 .

17. The method of claim 1 , wherein the absorber layer comprises selenium.

18. The method of claim 1 , wherein a grain size of the absorber layer is increased during annealing of the absorber layer.

19. The method of claim 1 , wherein the group V salt is ammonium dihydrogen arsenate.

20. The method of claim 1 , wherein the group V salt is diammonium hydrogen phosphate.

21. The method of claim 1 , wherein the group V element is nitrogen.

22. The method of claim 1 , wherein the group V element is phosphorous.

23. The method of claim 1 , wherein the group V element is arsenic.

24. The method of claim 1 , wherein the group V element is antimony.

25. The method of claim 1 , wherein the group V element is bismuth.

26. The method of claim 1 , comprising exposing an absorber layer to a reducing environment, while the absorber layer is annealed.

27. The method of claim 26 , wherein the reducing environment comprises a forming gas configured to mitigate formation of group V oxides, the forming gas comprising hydrogen, nitrogen, carbon, or combinations thereof.

Assignees

• First Solar Inc

Inventors

• Grover Sachit
• Lu Dingyuan
• Malik Roger
• Xiong Gang

Classifications

• H10P32/17

  characterised by the semiconductor material · CPC title

• H10P32/14

  within a single semiconductor body or layer in a solid phase; between different semiconductor bodies or layers, both in a solid phase · CPC title

• H10F77/1237

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

• H10F77/1233

  characterised by the dopants · CPC title

• H10F10/162

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