A nanoscale characterisation of extended defects in glassy-like As₂Se₃ semiconductors with PAL technique

O. Shpotyuk, A. Kovalskiy, J. Filipecki, M. Hyla, A. Kozdras.

Physica B, vol. 340–342, 2003, p. 960–964.

Abstract

A meaningful interpretation of positron lifetime characteristics for glassy-like g-As₂Se₃ is developed taking into account calculations of Jensen et al. (J. Non-Cryst. Solids 170 (1994) 57) for positrons trapped by free-volume extended defects in orthorhombic As₂Se₃ and void volume distribution for 146-atoms layer-biased model of amorphous As₂Se₃ presented by Popescu (J. Non-Cryst. Solids 35–36 (1980) 549). The obtained results are compared for samples having different thermal pre-history. Two groups of experimental results with close lifetime characteristics are distinguished for each of the investigated samples. This feature is explained in terms of average positron lifetime by applying two-state positron trapping model for mathematical treatment of the obtained spectra.