Phase diagram of In-Se system and crystal growth of indium monoselenide

An equilibrium phase diagram of the In-Se system was investigated in detail by differential thermal analysis (DTA). It was confirmed experimentally that the maximum conversion rate of the InSe crystal as the primary crystal is obtained from an In1.04Se0.96 melt. Composition analyses of ingots grown by the Bridgman method were performed using a He+ion Rutherford-backscattering technique (RBS). The results of the analyses were well consistent with the obtained phase diagram. To appreciate the quality of the InSe crystal, X-ray Laue and ion-blocking patterns, and energy dependance of channeled ions were investigated. These studies indicated that the InSe crystals had no mosaic structure. The values of electron mobility and decay time of photo-excited carriers also indicated the strong improvement of crystal perfection by the non-stoichiometric Bridgman method.