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

Publication date: 30 November 2017
Source:Thin Solid Films, Volume 642
Author(s): Joana Loureiro, Tiago Mateus, Sergej Filonovich, Marisa Ferreira, Joana Figueira, Alexandra Rodrigues, Brian F. Donovan, Patrick E. Hopkins, Isabel Ferreira
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 460μV/K and −320μV/K were achieved for p- and n-type films, respectively, with crystalline size in the range of 10nm, leading to remarkable low thermal conductivity values (<10W.m⁻¹.K⁻¹) at room temperature.