Type conversion, contacts, and surface effects in electroplated CdTe films

Abstract
Efficient electroplated CdS/CdTe solar cells can be fabricated by heat treating and type‐converting the n‐CdTe films deposited on CdS layers. In this paper, various mechanisms which may give rise to the conversion of electroplated CdTe films from n to p type are investigated. It is concluded that Cd‐vacancy generation is the main mechanism of type conversion. Possible effects of oxygen on this mechanism are also discussed. Evaporated Au contacts to electroplated p‐CdTe films were studied. It was found that the Au contacts depleted the excess Te present on the surface of Br2‐methanol etched p‐CdTe films. Oxygen was found to affect the electrical characteristics of such contacts.