The effect of sputtering power on structural, mechanical, and electrical properties of Copper Selenide Thermoelectric thin films deposited by magnetron sputtering

Abstract

Copper Selenide (Cu2Se) has received much attention as a potential thermoelectric and environmentally friendly material because of its exceptional thermoelectric performance. This study shows how Cu2Se thin films' structural, morphological, mechanical, and electrical properties are affected by varying the sputtering power deposited by radio frequency magnetron sputtering. By varying the sputtering power, the as-deposited Cu2Se thin film thickness values ranged from 436 to 1139 nm, measured by the stylus profilometer. Grazing incidence X-ray diffraction analysis was conducted to ascertain the phases present in the deposited films. It was observed that at higher sputtering power of 110 W, the Cu2-xSe phase was formed. Field Emission Scanning Electron Microscopy studies revealed that Cu2Se thin films deposited under varying sputtering power possess well-defined crystallinity with uniform distribution over the glass substrate. The grain size of the films increased with an increase in sputtering power. The nanoindentation studies showed that with varying sputtering power from 30 W to 110 W, hardness increased, having a maximum value of 2.4 ± 0.47 GPa for 110W sputtered film. The highest power factor of 15.6 μ W/cmK2 was achieved for a 110 W sputtered sample measured at a temperature of 450 °C, which is higher than that of all Cu2Se thin films, sputtered at different power.