Bandgap tuning of optical and electrical properties of zinc selenide

Abstract

Zinc Selenide (ZnSe) as an important II-VI semiconductor and one of the first semiconductors discovered with a band gap of around 2.7 eV at 25 °C. ZnSe thin films have been deposited 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. It has been found that the energy bandgap of semiconductor thin films tend to decrease as the temperature increases. Optical properties of the synthesized films were investigated by UV-VIS spectrometer in the wavelength range of 400-1000 nm. Energy band gap of films were calculated and variation due to variation in the thickness were observed. The least band gap value was found to be 1.92 eV for 150 nm thin at 2000C.The band gap results show the semiconducting nature of films grown. XRD technique was used to study the structural properties and the Hall measurement and I-V characteristics were used to study the electrical properties of the thin films. Hall characteristic of the ZnSe thin films for 150 nm at room temperature show that the material has p-type semiconducting nature which remains same if annealed to 2000C.