Abstract:
In the present work, a coating unit for depositing thin films has been developed
which works on the technique ―Closed Space Sublimation‖ where powdered material
is deposited under vacuum. Zinc Telluride thin films have been deposited on a glass
substrate. Structural, morphological, compositional, optical, and electrical properties
of the samples have been determined before and after doping. The main goal is to
enhance p-type conductivity of ZnTe thin films using Bismuth as dopant. The optical
properties of the films are also very important from the application point of view so
that improvement in conductivity and reduction in resistivity clearly achieved.
The structure of the films was studied by XRD, SEM and composition of the films
was measured by EDX. A Swanpoel model is used for the calculation of optical
parameters (optical band gap, refractive index, and films thickness) from the optical
transmission spectra recorded by spectrophotometer.
To reduce the resistivity of the thin films, Bismuth was doped. Bismuth was doped
using Closed Space Sublimation unit and doped film were vacuum annealed at
different temperatures in order to diffuse it in as-deposited samples of ZnTe .XRD
results confirmed the diffusion and formation of Bismuth with in ZnTe.
