Low temperature liquid phase growth of crystalline InSe grown by the temperature difference method under controlled vapor pressure

•InSe crystal was successfully grown by liquid phase growth.•Growth temperature is lower than that in the Bridgman-Stockbarger technique.•Large part of the ingot was high quality γ-InSe single crystal. Indium selenide (InSe), which is one of the most promising layered III-chalcogenide compounds, is an attractive material for applications in infrared detection, solar energy conversion and high mobility transfer devices etc. In this work, InSe crystals were grown from the liquid phase using the temperature difference method under controlled vapor pressure (TDM-CVP) at a growth temperature of 582 °C, which is lower than that of the melt used in the Bridgman-Stockbarger technique. X-ray diffraction (XRD) and Raman spectroscopy results indicate that the grown crystal was γ-InSe with R3m space group symmetry. Photoluminescence measurements were carried out to determine the optical properties of the grown crystal, from which it was confirmed that the sample had a direct bandgap of 1.32 eV, an indirect bandgap of 1.28 eV and an exciton binding energy of 20 meV.