DEPENDENCE OF TRANSPORT AND OPTICAL-PROPERTIES OF AMORPHOUS SBSE FILMS ON TEMPERATURE OF HEAT-TREATMENT

Transport and optical properties of amorphous and crystalline SbSe thi n films and the effect of annealing temperature on these properties ha ve been investigated. X-ray diffraction and electron microscope techni ques were used to get an insight into the structural information. SbSe is a layer semiconductor of orthorhombic crystal structure with latti ce constants a = 11.589 angstrom, b = 11.765 angstrom and c = 3.958 an gstrom. From the electrical conductivity measurements at various tempe ratures (76-473K), two processes of the dc conductivity in SbSe thin f ilms have been observed: (1) band conduction mechanism and (2) hopping conduction in localized states. The thermoelectric power measurements indicate that SbSe films are of p-type conduction. From the reflectio n and transmission data, the values of absorption coefficient (alpha) have been computed for amorphous and crystalline films. The analysis o f the absorption coefficient data revealed the existence of indirect t ransition with optical energy gap E(g)opt = 1.07 eV at 300K, which dec reases with increasing annealing temperature. The frequency dependence of the optical constants n, k, epsilon' and epsilon'' has also been c omputed.