Method of etching a semiconductor layer of a photovoltaic device

Abstract

A method and apparatus provide for a roughened back surface of a semiconductor absorber layer of a photovoltaic device to improve adhesion. The roughened back surface may be achieved through an etching process.

1 - 26 . (canceled) 
     
     
         27 . A photovoltaic device comprising:
 a window layer;   an absorber layer forded over the window layer, the absorber layer having a back surface, wherein the back surface has a roughness mean value of about 10 nm or greater; and   a conductive material formed in contact with the back surface of the absorber layer.   
     
     
         28 . The device of  claim 27 , wherein at least a portion of the back surface of the absorber layer is etched to achieve a roughness mean value of about 10 nm or greater. 
     
     
         29 . The device of  claim 27 , wherein the absorber layer is selected from the group consisting of: CIGS, CdTe, and amorphous Si. 
     
     
         30 . The device of  claim 27 , wherein the absorber layer comprises CdCl2-treated CdTe. 
     
     
         31 . The device of  claim 30 , wherein the absorber layer is heated in the range of about 380° C. to about 450° C. 
     
     
         32 . The device of  claim 27 , wherein the window layer is selected from the group consisting of ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, MgO, MgS, MgSe, MgTe, HgO, HgS, HgSe, HgTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InS, InN, InP, InAs, InSb, TIN, TIP, TIAs, TlSb, and mixtures thereof. 
     
     
         33 . The device of  claim 27 , wherein the conductive material is selected from the group consisting of metallic silver, nickel, copper, aluminum, titanium, palladium, chrome and molybdenum. 
     
     
         34 . The device of  claim 27 , wherein the absorber layer is doped with a with a p-type dopant. 
     
     
         35 . The device of  claim 34 , wherein the p-type dopant is selected from the group consisting of Li, Na, K, Rb, Cs, Cu, Ag, Au, N, P, As, Sb, and Bi.