Transport properties of 2D chalcogenides and their heterostructures a DFT study

Abstract

The industrial demand for energy is increasing at a very high rate with the advancement in technology. To fulfill this demand, fossil fuels and non-renewable resources are used. The overutilization of natural resources led to the deficiency of these resources for future generations. The goal of this thesis is to explore cost-effective and highly efficient thermoelectric materials. We have looked into the electronic and thermoelectric properties of chalcogen based two dimensional materials using density functional theory and Boltzmann transport theory. First, we studied the electronic and thermoelectric properties of Janus Al2SX (X= Se, Te) monolayers. These monolayers are efficient thermoelectric materials and can be used as potential candidates for the fabrication of thermoelectric devices. The effect of biaxial strain on the electronic structure and transport coefficients of AlX, MoX2 (X= S, Se) and GaS monolayers have also been investigated and found that the application of biaxial strain is one of the best ways to enhance the power factor of the considered material and which will be very helpful in enhancing the efficiency of thermoelectric materials. We also investigated the electronic band structure and transport properties of GaN-MoS2 hetero- structure. The electronic transport coefficient shows that p-type GaN-MoS2 heterostructures have a higher magnitude of power factor than n-type heterostructures and could be utilized to make efficient thermoelectric devices. Overall, the findings of this thesis emphasise the potential of 2-D chalcogenides for thermoelectric applications. newline