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 Eg and the average heats of atomization Hs were observed. The results indicated that both the number of topological constant Ncon and the radial and angular Nα, Nβ 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 Nco, the type of bonds, the degree of cross-linking and the band energy forming the network.