Improved thermoelectric properties of nanocrystalline hydrogenated silicon thin films by post-deposition thermal annealing

The influence of post-deposition thermal annealing on the thermoelectric properties of n- and p-type nanocrystalline hydrogenated silicon thin films, deposited by plasma enhanced chemical vapour deposition, was studied in this work. The Power Factor of p-type films was improved from 7 × 10− 5 to 4 × 10− 4 W/(m.K2) as the annealing temperature, under vacuum, increased up to 400 °C while for n-type films it has a minor influence. Optimized Seebeck coefficient values of 460 μV/K and − 320 μV/K were achieved for p- and n-type films, respectively, with crystalline size in the range of 10 nm, leading to remarkable low thermal conductivity values (< 10 W.m− 1.K− 1) at room temperature.