Doping effect of MnS on the electrical properties of CdS nano-crystalline films

Thin films of Cd1-xMnxS (0 ≤ x ≤ 0.5) were formed on window glass substrates by resistive vacuum thermal evaporation. All the films were deposited at room temperature and annealed at 100 degC, 200 degC and 300 degC for one hour in a vacuum of 10-6 torr. The as-deposited and the annealed films were characterized by EDAX, XRD, AFM, electrical conductivity and Hall Effect studies. Conductivity was studied in the temperature range 190-450 K. AFM studies showed that all the films investigated were in nano crystalline form with the grain size lying in the range 36-82 nm. The films with up to x = 0.3 exhibited hexagonal phase of CdS however films with x > 0.3 showed a complex phase. An interesting observation made was that conductivity, hall mobility, carrier concentration and grain size all exhibited maximum or minimum at x = 0.3. (author)