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

Abstract

Indium selenide (InxSey), 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 InxSey 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 InxSey 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 InxSey synthesis and pave the way for the optoelectronic applications.