O. Shpotyuk, V. Balitska.
Journal of optoelectronics and advanced materials, vol. 8, No. 6, 2006, p.2070-2076.
A microstructural mechanism of photoinduced transformations in amorphous films of arsenic selenide was studied with IR Fourier-spectroscopy technique in 300-100 cm-1 region. It was shown that stage of irreversible photostructural changes was connected with cooperative process of coordination defect formation accompanied by homopolar chemical bonds switching in heteropolar ones. On the contrary, reversible photoinduced effects were caused by heteropolar chemical bonds switching in homopolar ones, as well as additional channel of bridge heteropolar bonds switching in short-layer ones. The both processes were associated with formation of anomalously coordinated defect pairs and accompanying atomic displacements at the level of medium-range ordering. The developed mathematical simulation procedure testified that the observed kinetics of reversible photo-induced transformations corresponded to well-known stretched-exponential relaxation function, tending to bimolecular behavior rather then to single-exponential monomolecular one.