AN IN-SITU RAMAN-STUDY OF POLARIZATION-DEPENDENT PHOTOCRYSTALLIZATIONIN AMORPHOUS SELENIUM FILMS

Photocrystallization of amorphous selenium (a-Se) films under illumina tion by polarized light with 632.8 or 647.1 nm wavelength has been stu died by Raman spectroscopy. Preferential orientation of trigonal cryst alline, selenium (t-Se) obtained as a result of photocrystallization h as been observed, threefold c axis of t-Se being oriented perpendicula r to the direction of the polarization of the illuminating light. Alth ough the mechanism of polarization-dependent photocrystallization seem s to be optical in origin, an alternative, essentially thermal, mechan ism of the polarization-dependent photocrystallization of a-Se is disc ussed. (C) 1998 American Institute of Physics. [S0003-6951(98)02710-7] .