EN10.08.13 : Interface Effect of MoS2 on the Electrical and Thermoelectric Properties of Bi2Te3/MoS2 and Sb2Te3/MoS2 Composite

5:00 PM–7:00 PM Apr 4, 2018 (America - Denver)

PCC North, 300 Level, Exhibit Hall C-E

Mujeeb Ahmad1 Deepak Varandani1 Bodh Raj Mehta1

1, Indian Institute of Technology Delhi, New Delhi, , India

Molybdenum disulphide (MoS2) has attracted much attention in thermoelectric application because of its high carrier mobility and tunable electronic and thermal properties which can be tailored by controlling the number of layers. Bismuth telluride (Bi2Te3) and antimony telluride (Sb2Te3) are the most efficient thermoelectric materials at the room temperature. In the present study, we have prepared nanocomposite samples of Bi2Te3, (Bi2Te3/MoS2) and Sb2Te3 , (Sb2Te3/MoS2) using MoS2 nanoflakes. The effect of incorporating MoS2 nanoflakes on electronic and thermoelectric properties Bi2Te3/MoS2 and Sb2Te3/MoS2 nanocomposite samples have been studied. The value of ZT was calculated to be 0.77 and 0.48 for Bi2Te3/MoS2 and Bi2Te3 samples, respectively, at room temperature. Similarly, ZT value of 0.18 and 0.28 was calculated at 427 K for Sb2Te3 and Sb2Te3/MoS2 samples, respectively. Both nanocomposite samples show higher ZT values as compared to the corresponding pristine samples. In the case of Bi2Te3/MoS2, the enhancement in ZT is due to decrease in thermal conductivity, whereas, in Sb2Te3/MoS2 it is due increase in the power factor. This difference can be attributed to the difference in behavior of Bi2Te3/MoS2 and Sb2Te3/MoS2 interfaces. Kelvin probe force microscopy (KPFM) has been employed to determine the surface potential values of the pristine and nanocomposite samples. The above study shows that the surface potential value at Bi2Te3/MoS2 interface is lower by 300 mV as compared to Bi2Te3 and in case of Sb2Te3/MoS2 surface potential is observed to be 150 mV lower as compared to Sb2Te3. This decrement of the surface potential value shows higher work function at the interface in comparison to the pristine sample. The interface energy barrier in Bi2Te3/MoS2 and Sb2Te3/MoS2 nanocomposite samples is expected to modify electron/hole transport and phonon scattering.