Exploring Newly Discovered Semiconducting Phases of Tin Monoselenide using XAS and HR-SXRD

This project is aimed at the study of the physical and structural properties of two newly discovered semiconducting phases of tin monoselenide, pi-SnSe and gamma-SnSe. Both differ in properties compared to the conventional phase α-SnSe, and the latter shows an ultra-small bandgap and subsequently, very high electrical conductivity. The ultimate goals of the proposal are (i) to employ XAS techniques for investigation of the local symmetry of the constituting elements, Sn and Se, in the pi-SnSe and gamma-SnSe phases with respect to alpha-SnSe. (ii) to use temperature resolved measurements for monitoring the evolution of phase transitions of these new phases. (iii) to elucidate the role of small amounts of Pb2+ cations in stabilizing π-SnSe. The results are expected to shed light also on the unique optical and electronic properties of these two new phases of tin monoselenide.