Effect of diffusion length and surface recombination on the photopleochroism of anisotropic crystals

Formulas were derived and numerical analysis was carried out for the depend ences of photopleochroism coefficient P-i of the homogeneous anisotropic cr ystal on the diffusion length L and surface recombination rate. The polariz ation photoconductivity was considered in the region of both weak and stron g optical absorption. The spectral contour of photopleochroism was shown to follow the optical dichroism curve at weak absorption and deviated from it or even reversed in sign in the case of appreciable recombination of charg e carriers at the crystal surface at strong absorption. The limiting cases of zero and high surface recombination rates were considered for the depend ence of the photopleochroism coefficient on the diffusion length. The depen dences were analyzed by using the typical parameters of II-IV-V-2 ternary d iamond-like semiconductors. (C) 2000 MAIK "Nauka/Interperiodica".