Journal of Materials Science, Vol.35, No.10, 2619-2624, 2000
Study of trap levels by electrical techniques in p-type CuInSe2 thin films prepared using chemical bath deposition
CuInSe2 thin films, prepared using the Chemical Bath Deposition (CBD) technique, were analysed using Thermally Stimulated Current (TSC) measurements in order to get a clear picture of the different trap levels present in it. As-prepared samples showed two trap levels: the prominent one was due to the presence of a Se vacancy, while the weak one was due to the presence of a Cu vacancy. After annealing in air, the Se vacancy disappeared and a new level appeared which is suspected to be due to adsorbed oxygen. But annealing in air does not affect the Cu vacancy. On the other hand, annealing in vacuum does not affect Se vacancy, but the presence of an Fe impurity was detected in this case. A possible explanation for this phenomenon is also discussed. The dark conductivity measurements were also conducted on as-prepared as well as annealed CuInSe2 samples. These results are found to be in good agreement with the results obtained from TSC measurements.