Optical Study of a-Ge_5Se_(95-x)Te_x: Effect of Crystallization

摘要

Amorphous Ge_5Se_(95-x)Te_x (where x = 0, 2, 5 and 10) thin films deposited by thermal evaporation were annealed at different temperatures below their crystallization temperatures. The optical band gap has been studied of as-deposited and annealed films as a function of photon energy in the wave length range (400 - 900 nm). It has been found that the optical band gap increases with increasing annealing temperatures and on Te concentration in the present system. For as-deposited films: it has been found that refractive index (n) and the extinction coefficient (k) increases on incorporation of tellurium in Ge-Se system.