Photovoltaic device electrical contacts

Abstract

Photovoltaic cells including silicon solar cells are provided. A silicon substrate having an n-type silicon layer is provided with a silicon nitride layer, a reactive metal in contact with said silicon nitride layer, and a non-reactive metal in contact with the reactive metal. This assembly is fired to form a low Shottky barrier height contact comprised of metal nitride, and optionally metal silicide, on the silicon substrate, and a conductive metal electrode in contact with said low Shottky barrier height contact. The reactive metal may be titanium, zirconium, hafnium, vanadium, niobium, and tantalum, and combinations thereof, and the non-reactive metal may be silver, tin, bismuth, lead, antimony, arsenic, indium, zinc, germanium, nickel, phosphorus, gold, cadmium, berrylium, and combinations thereof.

1 . A photovoltaic device, comprising:
 a silicon substrate comprising an n-type silicon layer;   a low Schottky barrier height contact disposed on and adhered to said n-type silicon layer, said contact comprised of a metal nitride wherein the metal is selected from titanium, zirconium, hafnium, vanadium, niobium, and tantalum and combinations thereof;   a conductive metal electrode adhered to and disposed on said low Schottky barrier height contact.   
     
     
         2 . The photovoltaic device of  claim 1  wherein the low Schottky barrier height contact is further comprised of a metal silicide. 
     
     
         3 . The photovoltaic device of  claim 1  wherein the conductive metal is selected from silver, tin, bismuth, lead, antimony, arsenic, zinc, germanium, nickel, phosphorus, gold, cadmium, berrylium, and combinations thereof. 
     
     
         4 . The photovoltaic device of  claim 1  wherein the low Schottky barrier height contact disposed on and adhered to said n-type silicon layer is comprised of titanium nitride. 
     
     
         5 . The photovoltaic device of  claim 1  wherein the low Schottky barrier height metal nitride contact disposed on and adhered to said n-type silicon layer comprises part of a front electrode of said photovoltaic device.