Electron and thermal transport via Variable Range Hopping in MoSe$_{2}$ single crystals

Abstract: Bulk single crystal Molybdenum diselenide has been studied for its electronic and thermal transport properties. We perform resistivity measurements with current in-plane (CIP) and current perpendicular to plane (CPP) as a function of temperature. The CIP measurements exhibit metal to semiconductor transition at $\simeq 31$ K. In the semiconducting phase ($T > 31$ K), the transport is best explained by variable range hopping (VRH) model. Large magnitude of resistivity in CPP mode indicates strong structural anisotropy. Seebeck coefficient as a function of temperature measured in the range $90 - 300$ K, also agrees well with the VRH model. The room temperature Seebeck coefficient is found to be $139$ $\mu$V/K. VRH fittings of the resistivity and Seebeck coefficient data indicate high degree of localization.