An in situ Raman study of polarization-dependent photocrystallization in amorphous selenium films

Abstract
Photocrystallization of amorphous selenium (a-Se) films under illumination by polarized light with 632.8 or 647.1 nm wavelength has been studied by Raman spectroscopy. Preferential orientation of trigonal crystalline, selenium (t-Se) obtained as a result of photocrystallization has been observed, threefold c axis of t-Se being oriented perpendicular to the direction of the polarization of the illuminating light. Although the mechanism of polarization-dependent photocrystallization seems to be optical in origin, an alternative, essentially thermal, mechanism of the polarization-dependent photocrystallization of a-Se is discussed.