Microhardness and structural defects of GaSe layered semiconductor

Microhardness of GaSe layered single crystals was studied. The dependences of Vickers microhardness on load and time under load were studied experimentally to find a range of these parameters acceptable for reliable measurements. A range of loads was found, where time under load had no significant effect on microhardness. Mechanisms of deformation under concentrated load are discussed. The GaSe crystals showed anisotropy of microhardness in the (0 0 0 1) plane; the coefficient of anisotropy is k=Hmax/Hmin=1.4. Profiles of indentations and topography of the surface in the vicinity of an indentation were studied by atomic force microscopy (AFM). The experiment demonstrated good agreement between the calculated and the measured depths of indentation pits. AFM proved to be an informative technique for the description of a structure of the material after microindentation. Basal and non-basal dislocations were studied by optical microscopy and AFM.