LIQUID ENCAPSULATED CRYSTAL-GROWTH AND ELECTRICAL-PROPERTIES OF SB2SE3 AND BI2S3

Crystals of Bi2S3 and Sb2Se3 were grown by the liquid encapsulated solidification method. Dependence of their electrical resistivities on stoichiometry was studied. Sb2Se3 crystals grown after in situ synthesis are compensated and behave as an intrinsic-like material with a relatively narrow homogeneity range. Experimental data do not lend support to the hypothesis that the degenerate conductivity of some antimony selenide crystals is due to an excess of antimony. Instead, impurities and/or macroscopic defects could be responsible for a high hole concentration. Doping of both compounds was attempted. A self-compensation-like effect prevents Bi2S3 from undergoing n- to p-type conversion. It is possible to obtain p-type Sb2Se3 with relatively low resistivity by lead doping. However, both compounds exhibit quite weak sensitivity to impurities.