SnTe monolayer: Tuning its electronic properties with doping

Two-dimensional (2D) group IV monochalcogenides have attracted extensively attention due to their specific electronic properties and promising applications. The atomic-thick SnTe is an exemplar in 2D group IV monochalcogenides and shows robust ferroelectric properties at room-temperature. Using first principles calculation based on the density functional theory, we investigated the effects of doping on geometric structure, formation energy, band structure and carrier effective mass of SnTe monolayer. The results indicate that the radii and outermost valence electrons of doped atoms significantly affect the geometric structure and electronic structure of the doped compounds. The SnTe monolayer with donor (acceptor) impurities could be transformed into n-type (p-type) degenerate semiconductors with smaller electronics (holes) effective mass. Moreover, the direct bandgap semiconductors were obtained in this study by doping M_IV or X_VI in SnTe monolayer. The electrical conductivity and photoelectric conversion efficiency can also be improved by doping atoms in SnTe monolayer. These intriguing results make doped SnTe monolayers promising candidate materials for thermoelectric or photoelectric devices.