Hexagonal phase epitaxial cadmium sulfide on copper indium gallium selenide for a photovoltaic junction

Patent metadata

Field	Value
Publication number	US-10446706-B2
Application number	US-201615153478-A
Country	US
Kind code	B2
Filing date	May 12, 2016
Priority date	May 15, 2015
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

A method of manufacturing a photovoltaic structure includes forming a p-type semiconductor absorber layer containing a copper indium gallium selenide based material over a first electrode, forming a n-type cadmium sulfide layer over the p-type semiconductor absorber layer by sputtering in an ambient including hydrogen gas and oxygen gas, and forming a second electrode over the cadmium sulfide layer.

First claim

What is claimed is:

1. A method of manufacturing a photovoltaic structure, comprising:
forming a p-type semiconductor absorber layer comprising a copper indium gallium selenide based material over a first electrode;
forming a single crystal n-type cadmium sulfide layer having a predominant hexagonal crystal structure over the p-type semiconductor absorber layer by sputtering in an ambient including hydrogen gas and oxygen gas, the ambient having a partial pressure of the hydrogen gas that is greater than a partial pressure of the oxygen gas by 1.25 mTorr to 1.875 mTorr, wherein during the sputtering cadmium atoms from the n-type cadmium sulfide layer diffuse into an upper portion of the p-type semiconductor absorber layer to form a n-type cadmium doped copper indium gallium selenide semiconductor upper portion of the semiconductor absorber layer and thereby create a p-n junction between a p-type copper indium gallium selenide semiconductor lower portion of the absorber layer and the n-type cadmium doped copper indium gallium selenide semiconductor upper portion of the absorber layer; and
forming a second electrode over the cadmium sulfide layer,
wherein the ambient consists essentially of an inert sputter gas having a partial pressure in a range from 2.5 mTorr to 7.5 mTorr; the hydrogen gas having a partial pressure in a range from 1.25 mTorr to 3.75 mTorr; and the oxygen gas having a partial pressure in a range from 0.875 mTorr to 1.5 mTorr; and
wherein the step of forming the n-type cadmium sulfide layer by sputtering comprises sputtering the n-type cadmium sulfide layer from a CdS target in the ambient.

2. The method of claim 1 , wherein:
the ambient includes an inert sputtering gas; and
a total pressure of the ambient is in a range from 5 mTorr to 10 mTorr.

3. The method of claim 1 , wherein:
hydrogen gas is flowed into a sputtering chamber at a first flow rate;
oxygen gas is flowed into the sputtering chamber at a second flow rate; and
a difference between the first flow rate and the second flow rate is in a range from 30 sccm to 80 sccm.

4. The method of claim 1 , wherein forming the n-type cadmium sulfide layer comprises forming a single crystal intrinsically doped or zinc doped cadmium sulfide layer having the predominant hexagonal crystal structure by the sputtering in the ambient.

5. The method of claim 1 , wherein forming the n-type cadmium sulfide layer comprises forming a single crystal copper cadmium sulfide layer having the predominant hexagonal crystal structure by the sputtering in the ambient.

6. The method of claim 5 , wherein the single crystal copper cadmium sulfide layer is composed predominantly of one or more hexagonal phase cadmium sulfide grains.

7. The method of claim 1 , wherein forming the n-type cadmium sulfide layer comprises forming a first single crystal copper cadmium sulfide layer having the predominant hexagonal crystal structure by the sputtering in the ambient and forming a second single crystal cadmium sulfide layer having the predominant hexagonal crystal structure over the first single crystal copper cadmium sulfide layer by the sputtering in the ambient.

8. The method of claim 1 , wherein forming the second electrode comprises forming a zinc containing oxide layer such that zinc diffuses into the n-type cadmium sulfide layer to form a zinc doped cadmium sulfide layer.

9. The method of claim 8 , wherein oxygen and the zinc diffuse into the n-type cadmium sulfide layer to form a zinc and oxygen doped cadmium sulfide layer.

10. The method of claim 1 , wherein the n-type cadmium sulfide layer is doped with one or more of copper, zinc, oxygen or hydrogen.

11. The method of claim 1 , wherein the p-n junction is a homojunction.

12. The method of claim 1 , wherein the p-n junction is a p-n heterojunction.

Assignees

• Beijing Apollo Ding Rong Solar Tech Co Ltd
• Univ Illinois
• L Livermore Nat Security Llc

Inventors

• Mackie Neil
• Zapalac Geordie
• Zhang Weijie
• Corson John F
• He Xiaoqing
• Rockett Angus
• Varley Joel
• Lordi Vincenzo

Classifications

• H10P14/3428

  Sulfides · CPC title

• H10P14/3236

  being chalcogenide semiconducting materials not being oxides, e.g. ternary compounds · CPC title

• H10P14/22

  using physical deposition, e.g. vacuum deposition or sputtering · CPC title

• Y02E10/541

  CuInSe2 material PV cells · CPC title

• Y02E10/543

  Solar cells from Group II-VI materials · CPC title