Electronic and thermoelectric transport in two-dimensional layered-structure material

Electronic and thermoelectric transport properties have been the extensively studied topics in the two dimensional materials. Hicks and Dresselhaus predicted that the reduction in dimensionality of materials can enhance the thermopower power factor. However the observation of confinement-induced enhancement of thermoelectric power factor predicated by Hicks and Dresselhaus has been challenging. In this work, we firstly studied the electronic transport mechanism of InSe nanoflakes in the presence of the magnetic field and gate voltage. We observed the gate-tunable weak antilocalization phenomenon and a very long coherent length of up to 320 nm at 1.7 K. The scattering mechanisms were analysed in details. Furthermore, we investigated the thermoelectric properties in the InSe thin film and revealed that the Seebeck coefficient and power factor can be enhanced by the enhanced DOS arising from the size confinement effect when the thickness of InSe thin film is thinned down. Most importantly, we experimentally identified the condition for drastically enhancing the thermoelectric power factor in the 2D layered-structure materials.