Role of MoS 2 on the Electrical and Thermoelectric Properties of Bi 2 Te 3 and Sb 2 Te 3 Alloys

The effect of presence of MoS2 on the electrical and thermal conductivity of Bi2Te3 and Sb2Te3 has been studied. MoS2 nanoflake were observed to be randomly dispersed in the nanocomposite samples. The electrical conductivity of Sb2Te3:MoS2 was observed to be higher as compared to the pristine Sb2Te3 due to large carrier mobility of MoS2. However, in the case of Bi2Te3:MoS2, the incorporation of MoS2 led to the decrease in the value of electrical conductivity due to enhanced electron scattering at Bi2Te3/MoS2 interface. The power factor of Sb2Te3:MoS2 nanocomposite sample was observed to be higher as compared to pristine Sb2Te3 sample due to the higher electrical conductivity, whereas in the case of Bi2Te3:MoS2, the value of power factor is higher due to larger Seebeck coefficient value. The Scanning thermal microscope (SThM) images show that pristine and corresponding nanocomposite samples have different thermal conductivities. Bi2Te3:MoS2 sample shows low thermal conductivity while Sb2Te3:MoS2 sample exhibits higher power factor due to incorporation of MoS2.