Exploring particular electronic and optical properties of Tl2HgSnSe4, promising chalcogenide for solar photovoltaics and optoelectronics: A complex experimental and theoretical study

A nearly centimeter-size Tl2HgSnSe4 crystal was successfully derived by Bridgman-Stockbarger growth technique and its electronic and optical properties are investigated experimentally and theoretically. The present XPS experiments imply very little hygroscopic behavior of the Tl2HgSnSe4 crystal surface, a char-acteristic property to be very important for practical use of this crystal in devices working at ambient atmospheric conditions. The experimentally determined energy band gap, 1.26 eV, and high values of the photocurrent spectral dependence confirm that Tl2HgSnSe4 crystal is a high-resistance photosensitive semiconductor possessing the p-type conductivity. The finest agreement with the experiment is detected when the theoretical calculation of the electronic structure of Tl2HgSnSe4 is carried out using modified Becke-Johnson functional for the exchange-correlation potential and involving the Hubbard amendment parameter U and the spin-orbit coupling effect. The present experimental and theoretical data suggest good perspective of application of Tl2HgSnSe4 in optoelectronics and as a suitable material of solar photovoltaics.(c) 2023 Elsevier B.V. All rights reserved.