Effects of Fabrication Parameters and Operating Temperature on CDS Thin Film Electronic Properties
This paper is a study of the effects of fabrication parameters and operating temperature on CdS thin film electronic properties. In this research work only three fabrication parameters will be considered and they are annealing temperature, deposition rate and doping level, while on the other hand the electronic properties, which will be under investigation are surface and bulk resistances, I-V characteristics, carrier concentration and Hall mobility. In our previously published paper it was found that the best substrate temperature is 180oC and thickness 1.2µm. A number of samples of CdS thin film were fabricated with these parameters using vacuum thermal evaporation technique. The study and analysis of these samples show that and from I-V characteristic the current is directly proportional to the biasing voltage and annealing temperature while it is inversely proportional to deposition rate. The carrier concentration and Hall mobility are generally influenced by the annealing temperature. Carrier concentration decreases gradually with the increase of deposition rate and similarly the Hall mobility decreases with the increase of deposition rate and up to deposition rate of 6oA/sec where beyond this value it starts to increase. The resistance of the thin film on the whole decreases with the increase of the operation temperature and annealing temperature.
Index Terms - Cadmium Sulfide Thin Film, Annealing Temperature, Deposition Rate, Surface and Bulk Resistance, Carrier Concentration, Hall Mobility, Operating Temperature, Doping Level