Investigation of growth, structural, optical and electrical properties of GaSe and GaSe:Cd semiconductors

GaSe promises a variety of technological applications such as solar cells, infrared detectors and converters. Interest in this material is increasing day by day. In this work, GaSe and GaSe:Cd semiconducting compounds were grown by Modified Bridgman-Stockbarger method, Structural electrical and optical properties of the grown semiconductors were investigated. The structural, morphological and compositional properties of the samples were determined using XRD, SEM, AFM and EDAX techniques. XRD results showed that the amplified samples had a hexagonal crystal structure and reduced peak intensities of Cd doping. Using XRD results, the lattice parameters of the samples were calculated as a = b = 3,749 Å and c = 15,907 Å. From the SEM and AFM results, it was observed that the mean particle size and the samples were homogeneous, and Ga, Se, and Cd elements were detected in the EDAX technique samples. Magnetoresistance coefficient, carrier density, Hall coefficient, mobility and electrical resistivity values of the samples were calculated with the help of electrical measurement, and the changes of these quantities depending on the temperature were studied. Then, current-voltage (I-V) characteristics of Au-Ge/p-GaSe:Cd diode were taken at 10 K steps in the temperature range of 40-360 K. It was seen that the barrier height decreased from decreasing temperature, calculated from ln (I) -V graph, and the ideal factors also increased. This change is explained by assuming that the barrier height of the metal semiconductors has a Gaussian distribution. The optical absorption measurements based on the temperature of the samples were taken at 10 K steps in the temperature range of 10-320 K. The variation of exciton and forbidden energy range depending on the temperature has been examined. It was observed that the Cd element GaSe samples doped into the structure increased the optical absorption intensity. With the annealing process, the intensity of absorption decreased and the band gap energy range increased in the samples.