Thermal decomposition study of SnSe single crystals

Single crystals of SnSe are grown by direct vapor transport technique. The elemental composition of as-grown crystals determined by dispersive X-ray energy analysis showed the crystals to be slightly selenium rich and tin deficient. The X-ray powder diffraction showed the crystal to possess orthorhombic unit cell structure. The lattice parameters are in good match with reported data. The surface micro-topography showed flat surfaces with layer edges, stating crystal growth to happen by mechanism of layer growth. The thermo-curves of the as-grown single crystals are recorded in temperature range of 308 K and 1053 K in inert nitrogen atmosphere. The curves are recorded for three thermal heating rates of 10, 15 and 20 K/min. The recorded thermogravimetric curves showed single-step decomposition. The single peak in differential thermogravimetric analysis further confirmed single-step decomposition. The differential thermal analysis of the samples showed initial exothermic followed by endothermic and at last exothermic nature. The thermodynamic variables determined from the thermo-curves data employing Kissinger relation stated absorption of heat leading to non-spontaneous decomposition.