Combustion synthesis of InSe, In2Se3, and GaSe

InSe, In2Se3, and GaSe are important III-VI semiconductors and are attractive for electronic, optical, and optoelectronic applications. This paper reports a fast and cheap way called combustion synthesis to prepare InSe, In2Se3, and GaSe. Bulk samples with relative densities up to 98% are directly produced in a few seconds. The samples show a high phase purity, correct stoichiometry, and lamellar crystals larger than 100 μm. By optical absorption, the bandgaps of InSe, In2Se3, and GaSe are determined to be 1.08, 1.24 and 1.75 eV, respectively.