INFLUENCE OF THE COOLING RATE ON THE ELECTRICAL-CONDUCTIVITY OF COEVAPORATED CUINS2 THIN-FILMS

We investigated the influence of the cooling rate in a deposition proc ess on the electrical conductivity a of CuInS2 thin films for solar ce lls. In situ measurements were used in order to monitor the electrical conductivity of Cu-poor films during growth and cooldown. It is shown that the room-temperature electrical conductivity sigma(RT) depends s ignificantly on the cooling rate of the film after deposition. sigma(R T) reaches 1 x 10(-3) S cm(-1) for a cooling rate of 2.0 +/- 0.2 K min (-1) whereas for abrupt cooling and higher cooling rates sigma(RT) is reduced to 10(-6) and 10(-5) S cm(-1), respectively. (C) 1997 American Institute of Physics.