Low resistance contact to CdTe thin films

Abstract

A new procedure to realize low resistance contact to polycrystalline CdTe thin films for solar cells deposited by CSS method is presented. Initially, the CdTe samples are etched with an oxidant agent in order to form a Te-rich surface layer; subsequently the CdTe samples are dipped in a CuCl solution to form a p/sup +/-Cu/sub x/Te (1/spl les/x/spl les/2) layer through an ion-exchange chemical reaction; finally, the samples were contacted with Cu and Cu/Au deposited by thermal evaporation and C:Cu deposited by DC magnetron sputtering. Contact resistivities of 0.16 /spl Omega/cm/sup 2/ were obtained using sulphochromic solution as oxidant agent and Cu as electrical contact. The changes induced in the CdTe-surface by the different surface treatments were studied by means of XRD and AES measurements.