KPFM based investigation on the nature of Sb2Te3:MoS2 and Bi2Te3:MoS2 2D interfaces and its effect on the electrical and thermoelectric properties

In this study, the effect of incorporation of 2D nanoflakes on an n type and a p type thermoelectric matrixes, Bi2Te3 and Sb2Te3, respectively, has been studied. MoS2 has been used to prepare nanocomposite bulk samples having n-n or n-p 2D interfaces. Kelvin probe force microscopy based measurements were used to characterize nanocomposite samples which revealed a difference in potentials barrier at the 2D interface for Bi2Te3:MoS2 and Sb2Te3:MoS2 samples, respectively. The electrical conductivity of Bi2Te3:MoS2 was observed to be lower as compared to the pristine Bi2Te3 due to increased electron scattering at 2D interfaces, whereas in the case of Sb2Te3:MoS2, the incorporation of MoS2 led to the increase in the value of electrical conductivity due to higher carrier mobility. In Bi2Te3:MoS2, a large decrease in thermal conductivity due to reduced electronic contribution is observed in contrast to no change in the case of the Sb2Te3:MoS2 nanocomposite sample. The Seebeck coefficient is observed to increase ...