Preparation of In_0.5Sn_0.5Se Crystal via a Zone Melting Method and Evaluation of its Thermoelectric Properties

Abstract

Indium selenides (InSe) is a promising layer‐structured semiconductor with broad potential applications in photovoltaics, diodes, and optic devices, but its thermoelectric performance is limited by the high thermal conductivity. In this work, by alloying high‐performance thermoelectric SnSe in InSe, the In0.5Sn0.5Se crystal is prepared via a zone melting method. The density of In0.5Sn0.5Se crystal is measured as 5.81 g cm−3 which is between the density of pure SnSe and InSe. The XRD measurements indicate that the grown In0.5Sn0.5Se crystal consists of InSe and SnSe crystals with a preferred orientation along (00l) and (h00) planes, respectively. SEM and EDS analysis reveal that eutectic InSe and SnSe phases interdigitate with each other. The thermogravimetry analysis shows a slow decrease at a temperature ≈700 °C. In0.5Sn0.5Se crystal displays a n‐type conduct behavior, the electrical conductivity σ is ≈0.02 Scm−1 at room temperature and increases to 8.4 Scm−1 under 820 K. The highest power factor PF is estimated to be ≈0.36 µWcmK−2 near 570 K. The InSe‐SnSe phase boundaries lead the thermal conductivity of In0.5Sn0.5Se crystal to be as low as 0.29 Wm−1K−1. Due to the low lattice thermal conductivity, In0.5Sn0.5Se crystal shows a ZT value of 0.04 at 600 K in this work.