Phase-controlled growth of indium selenide by metalorganic chemical vapor deposition

Abstract

Indium selenide (In_xSe_y), group III-VI semiconductor, has various crystal phases, so that the growth technique for controlling the crystal phase is necessary for studying the novel properties as well as the device applications. In this work, we demonstrate the phase-controlled growth of In_xSe_y using metalorganic chemical vapor deposition. As the growth temperature increases, the crystal phase changes from InSe, β-In₂Se₃ to γ-In₂Se₃, which can be explained by their thermal stability. Besides, as the gas-phase VI/III source molar ratio increases, the crystal phase changes from InSe to In₂Se₃, indicating that Se-rich surface stoichiometry results in Se-rich crystal phase, i.e. In₂Se₃. We summarized the crystal phases depending on the growth temperature and the VI/III source molar ratio as a phase diagram. The In_xSe_y growth near the phase boundary between InSe and β-In₂Se₃ take place under surface-reaction-limited regime and the dissociation of Se source mainly controls the surface stoichiometry. This phase diagram will be a guideline for the phase-pure In_xSe_y synthesis and pave the way for the optoelectronic applications.