Ambipolar Seebeck Coefficient in MoS₂/MoS₂–MoO₂ Graded Composites by Junction Reciprocation

We fabricated radially transformed growth of MoS 2 to MoS 2 –MoO 2 by the two-zone chemical vapor transport (CVT) technique. The idea to apply heat, i.e., hot junction ( T H ), on both the edges of the film has a distinct ambipolar Seebeck coefficient ( S ) of −20 μVK –1 with MoS 2 as hot junction, and 69.5 μVK –1 with MoS 2 –MoO 2 as hot junction. The positive S at MoS 2 –MoO 2 indicates fast hole injection at a lower degree of interface Fermi-level pinning and large asymmetry at the junctions through low energy carrier scattering in the multiple potential barriers at the interfaces of each region. The decreased Θ D around 5 K than MoS 2 reveals the lattice softening due to reduced strength of chemical bonding at MoS 2 –MoO 2 . The report propounds the potential utilization of multiple potential barriers for thin film graded composites in thermoelectric applications.