Investigation of optical and structural properties of multilayer thin films of Cadmium Selenide

Abstract

Multilayer Cadmium selenide (CdSe) thin films have been deposited on glass substrate by e-beam evaporation method with different thicknesses from 50 nm to 150 nm and effects of annealing temperature on optical and electrical properties of thin films have been investigated at room temperature (RT), 100⁰C and 200⁰C. X-ray diffraction (XRD) studies identify that the as-deposited CdSe films are amorphous in nature with no distant peak. Optical properties of the synthesized films were investigated by UV-VIS spectrometer in the wavelength range of 400-1000 nm. It has been found that the energy bandgap of semiconductor thin films tend to decrease as the temperature increases. Energy band gap of films were calculated and variations due to variation in the thickness were observed. The least band gap value was found to be 1.54 eV for 50 nm thin at 200⁰C.The band gap results show the semiconducting nature of films grown. Hall measurement and current-voltage characteristics were used to study the electrical properties of the thin films. Hall characteristic of the CdSe thin films for 50 nm at room temperature and at 200⁰C show that the material has p-type semiconducting nature.