Engineered cation vacancy plane responsible for the reduction in lattice thermal conductivity and improvement in the thermoelectric property of Ga2Te3-based semiconductors

Abstract

Based on the inherent Ga vacancies in Ga₂Te₃, we use the preferential occupation of Cu in the Ga lattice, which can be confirmed by calculating the formation energy and Rietveld refinement, to disturb the vacancy path, and thereby have cleverly manipulated the vacancy plane. Moreover, we revealed that the sample annealed for 30 days has generated raindrop-shaped discontinuous vacancy planes, which can effectively reduce the lattice thermal conductivity (k_L) and increase the bandgap (E_g), thus accounting for the remarkable improvement in thermoelectric performance. However, with the annealing time extending from 30 days to 95 days, there is a gradual enhancement in k_L and limited improvement in the thermoelectric property, which is caused by the amalgamation or restructuring of the discontinuous vacancy planes.