Investigation of composition effect on electrical properties of noncrystalline GeSe2−xSnx (0 ≤ x ≤ 0.8) thin films

Amorphous GeSe2−xSnx (0 ≤ x ≤ 0.8) films were papered by vacuum evaporation method. X-Ray diffraction conferred the amorphicity of these films. The direct current conductivity, σdc, of GeSe2-xSnx thin films have been carried out as a function of molar compositions in the temperature range of 298-444 K. The results show that σdc increased with increasing the Sn composition, which might be because of the move of Fermi level. In addition, the conductivity is a thermally invigorated process having two conduction mechanisms. In the high temperatures area, the conductivity has additionally been construed utilizing Meyer-Neldel rule. In the low temperatures area, the conductivity has been construed utilizing Mott's variable range hopping conduction and Mott's parameters were computed. Additionally, the current density-voltage characteristics have been measured for all thin film samples. The experimental data of all studied samples fits well with the theory of space charge limited conduction (SCLC). The density of state (DOS) has been ascertained utilizing SCLC measurement. The increasing in DOS with increasing of concentricity of Sn might be because of the increasing in the defect states.