Optical Properties of Undoped and phosphours Doped Amorphous Germanium Thin Fitms

Measurement of the optical properties of pure and phosphours doped amorphous germanium thin films deposited at room · temperature (RT) onto glass substrates using flash evaporation method have been made as a function of annealing temperature from RT to 523K.The results shov.1ed that the optical energy gap ,8 constant ,refractive index, extinction coefficient , real and imaginary parts of the dielectric constants of the films decreased when doping with 2.5%phosphours.Also it is found that the increase of annealing temperature from RT to 523K caused an increase in the opti gap and B for pure and phosphours doped amorphous germanium films and slightly decrease in the refractive index, extinction coefficient , the real and imaginary parts of the dielectric constant at wavelength 11 OOnm for pure films, whereas it decreased after annealing at 473K then increased on further increase in the annealing temperature to 523K for phosphours doped amorphous germanium thin films