Investigation of the structural, electronic and thermoelectric properties of GeX (X=S, Se, Te) monochalcogenides

Electronic band structure calculations were performed using density functional theory (DFT) for the orthorhombic structure of GeS and GeSe compounds, and the trigonal structure of GeTe. These compounds exhibit a semiconductor behavior with band gaps of 1.23, 0.899, and 0.68 eV for GeS, GeSe and GeTe, respectively. Based on these DFT calculations their thermoelectric properties were obtained using Boltzmann transport theory. Different procedures were adopted to increase the thermoelectric properties of these compounds including doping and lowering the dimensionality.