Controllable indium doping for high efficiency czts thin-film solar cells

Patent metadata

Field	Value
Publication number	US-2016359076-A1
Application number	US-201514749272-A
Country	US
Kind code	A1
Filing date	Jun 24, 2015
Priority date	Jun 2, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A photovoltaic device includes a first contact layer formed on a substrate. An absorber layer includes Cu—Zn—Sn—S(Se) (CZTSSe) on the first contact layer. A buffer layer is formed in contact with the absorber layer. Metal dopants are dispersed in a junction region between the absorber layer and the buffer layer. The metal dopants have a valence between the absorber layer and the buffer layer to increase junction potential. A transparent conductive contact layer is formed over the buffer layer.

First claim

1 . A method for forming a photovoltaic device, comprising:
providing an absorber layer including Cu—Zn—Sn—S(Se) (CZTSSe) on a first contact layer formed on a substrate; forming a buffer layer in contact with the absorber layer; doping a junction region between the absorber layer and the buffer layer with metal dopants having a valence between the absorber layer and the buffer layer to increase junction potential; and forming a transparent conductive contact layer over the buffer layer.

2 . The method as recited in claim 1 , wherein providing an absorber layer includes providing Cu 2-x Zn 1+y Sn(S 1-z Se z ) 4+q wherein 0≦x≦1; 0≦y≦1; 0≦z≦1; −1≦q≦1.

3 . The method as recited in claim 1 , wherein forming a buffer layer includes forming a semiconductor material including one of Cd or Zn.

4 . The method as recited in claim 1 , wherein the buffer layer includes one or more of CdTe, CdS, ZnS, Zn(O,S) or ZnO.

5 . The method as recited in claim 1 , wherein the buffer layer includes CdS and the metal dopants include In metal.

6 . The method as recited in claim 5 , wherein the CZTSSe includes a valence of +4 for its Sn, the In metal includes a valence of +3 and the CdS includes a valence of +2 for its Cd.

7 . The method as recited in claim 1 , wherein doping a junction region includes depositing an ultrathin metal layer on the buffer layer.

8 . The method as recited in claim 7 , wherein depositing the ultrathin metal layer on the buffer layer includes employing a thermal evaporation process.

9 . The method as recited in claim 7 , further comprising performing an anneal to diffuse the ultrathin metal layer into the buffer layer for doping the junction region.

10 . The method as recited in claim 7 , wherein the ultrathin metal layer includes a deposited thickness of between about 0.1 nm to about 1.0 nm.

11 . The method as recited in claim 1 , wherein doping the junction region includes doping the junction region to a dopant concentration of between about 10 16 -10 21 atoms/cm 3 .

Assignees

• IBM

Inventors

• Gershon Talia S
• Kim Jeehwan
• Lee Yun Seog
• Todorov Teodor K

Classifications

• Y02E10/50

  Photovoltaic [PV] energy · CPC title

• H01L31/072

  Electricity · mapped topic

• H01L31/18 Primary

  Electricity · mapped topic

• H10F77/1285

  characterised by the dopants · CPC title

• H10F77/128

  comprising only Group I-II-IV-VI kesterite materials, e.g. Cu2ZnSnSe4 or Cu2ZnSnS4 · CPC title