Amorphous Ge5Bi18Se77 thin films deposited by thermal evaporation were crystallized by thermal annealing at their crystallization
temperature (Tc). The composition, determined using EDAX, does not indicate any significant variation in both as-deposited films and films annealed with different annealing rates from that of bulk alloy. The effect of annealing rate on the nature and the degree of crystallization
has been investigated by studying the structure using TEM/XRD and the surface morphology using SEM. It is found that the
annealed films crystallized into a face centred cubic (FCC) phase with a lattice constant of 6:2084 0:0015 A . Further, it is also seen that depending on the annealing rate, the as-deposited films crystallized into either single crystal films or polycrystalline films. A detailed analysis of the structural properties has been presented.