Optical, electrical and the related parameters of amorphous Ge-Bi-Se thin films

The related optical and electrical parameters of amorphous Ge-Bi-Se thin films were studied. The dependence of optical and electrical properties on the Bi content was observed in most compositions. At Bi > 10 at% the behavior show a switch from p to n type conduction mechanism. The correlation between the optical band gap E-g and the average heats of atomization H-s were observed. The results indicated that both the number of topological constant N-con and the radial and angular N-alpha, N-beta valence force constants exhibit the same trend with increasing Bi content. On the other hand, the mean bond energy < E > increases with increasing Bi content to x = 15 at%. It may be concluded that < E > is a function of the mean coordination number N-co, the type of bonds, the degree of cross-linking and the band energy forming the network. (c) 2005 Elsevier B.V. All rights reserved.