High thermoelectric power factor in SnSe2 thin film grown on Al2O3 substrate

Thermoelectric figure of merit (ZT) is highly sensitive to the carrier concentration and maximizes within the narrow region of 1019–1020 cm−3. The SnSe2 single crystal is predicted to have a high ZT value with carrier concentration in the range of 1019–1020 cm−3. Here, we grew SnSe2 thin film on Al2O3 substrate by pulsed laser deposition (PLD) with post-annealing at 400 °C in Argon for 60 min. The annealed thin film shows a high thermoelectric power factor up to 8 μW cm−1 K−2 at 220 K with a carrier concentration of 5.2 × 1019 cm−3. A hexagonal crystal structure of the SnSe2 thin film was confirmed by X-ray diffraction and Raman spectra measurements. The thin film showed an n-type semiconductor behavior. Maximum electrical conductivity and Seebeck coefficient were obtained at 220 K with the values of 210 Scm−1 and −192 μVK−1, respectively.