Optical and electrical properties of ZnSe thin films: effect of vacuum annealing

摘要

Inert gas condensation method has been successfully employed for depositingZnSe thin films. These films have been deposited at argon gas partial pressure of 210-1mbar and room temperature (298 K). After deposition these films have been annealed(in vacuum at 473 K) for one hour. The optical and electrical properties of these filmshave been investigated before and after annealing using optical transmission andconductivity measurements. The absorption coefficient () and band gap (Eg) arecalculated using transmission curves. Optical transmittance measurements indicate theexistence of direct allowed optical transition with a corresponding energy gap in therange of 2.80".00 eV. The dark conductivity (d) and photoconductivity (ph)measurements, in the temperature range 253"58 K, indicate that the conduction inthese materials is through an activated process having two activation energies. d andph values increase with the annealing. The values of carrier life time have beencalculated and these values increase with the increase in the crystallite size onannealing. Thermal treatment has appreciable effect on above mentioned properties.