Electrical Properties of Recrystallised SiC Films from PECVD Precursors for Silicon Quantum Dot Solar Cell Applications
Year: 2011
Type: article
Abstract: Silicon carbide (SiC) is a promising host material for silicon quantum dots (Si QDs), which are being investigated as absorber materials for tandem solar cells based solely on crystalline silicon. Amorphous silicon carbide (a-SiC) films are deposited by plasma-enhanced chemical vapour deposition (PECVD) and annealed under the same conditions usually used to precipitate Si QDs. During annealing, the films shrink by 20%, and some a-SiC transforms into SiC nanocrystals (nc-SiC) about 3 nm in size. P-type doping with boron is found to inhibit SiC crystallisation and lower conductance as compared to intrinsic films. N-type doping with phosphorus on the other hand promotes SiC crystallisation and leads to a higher conductance. The trends in conductance are ascribed solely to the effect of the dopant on crystallisation. Al, Ti, Cr, Ni20%Cr, and ITO are all found to form Ohmic contacts to the SiC films on deposition, with no change in contact properties brought about by sintering at 425°C. Temperature-dependent conductivity measurements on intrinsic SiC films reveal two distinct activation energies; 65 meV below 200 K, and 158 meV above 200 K.
Source: PubMed
Institutions: Fraunhofer-Gesellschaft, University of Freiburg
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W10177512