An Optical and Electrical Study of a Ge Se In and a Ge Se In Bi Glassy Alloys

Abstract

This thesis work is concerned with the study of optical, electrical and physical properties of a-Ge-Se-In and a-Ge-Se-In-Bi glassy alloys and their corresponding thin films. Glassy alloys and their thin films prepared and studied are: newlineI. Ge20Se80-xInx (x = 0, 5, 10, 15, 20) newlineII. Ge20Se70-xIn10Bix (x = 2, 4, 6, 8, 10) newlineMelt quench technique has been used for the growth of glassy alloys. Thin films of prepared samples were deposited using thermal evaporation technique at base pressure of ~10-4 Pa. X-ray diffraction technique has been used to know the nature (amorphous or crystalline) of bulk and deposited films. The optical properties have been estimated by analyzing the transmission spectra (400 1800 nm) obtained from ultraviolet-visible-near infrared spectrometer. Swanepoel s method has been used to determine refractive index and extinction coefficient. Optical band gap has been calculated using Tauc extrapolation. The various electrical measurements on the thin films including both the dark and photoconductivity measurements at different temperatures were carried out in a metallic sample holder under a vacuum ~ 10-3 mbar throughout the measurements. Steady state photoconductivity has been studied in temperature range 303 375 K. Intensity dependent photocurrent has been measured in 3 - 1035 Lux range. Physical parameters of both a-Ge-Se-In and a-Ge-Se-In-Bi glassy alloys have been estimated. newline newline