Nitrogen doped chalcopyrites as contacts to CdTe photovoltaics

CuInSe₂, CuGaSe₂, and alloys thereof produced by a hybrid sputtering and evaporation method show evidence of being dopable with nitrogen by the replacement of some of the Ar sputtering gas with N₂. This results in a decrease in resistivity of the films with increasing N₂ pressure in the sputtering gas. No doping of AgInSe₂ or CuAlSe₂ has been observed to date following similar methods of deposition. The films are now being tested as back contacts to CdTe solar cells. To date only high resistance contacts have been obtained but more testing and improved CdTe cleaning techniques are required to obtain optimized contacts. The doped chalcopyrites represent potential materials for tunnel junctions for use in CIGS photovoltaics and other devices.