Blue emission from silicon-based β-SiC films

Abstract

β-SiC films were fabricated on 〈100〉- and 〈111〉-oriented silicon substrates by pulsed laser deposition. The photoluminescence (PL) spectrum shows two blue emissions at 416 and 435 nm. Their positions do not change with both the substrate orientation and β-SiC crystallite sizes. High-resolution transmission electron microscopy observations display that the fabricated films contain both β-SiC and Si nanocrystallites. Fourier-transform infrared absorption and electron paramagnetic resonance measurements provide the evidences that the radiative recombination of carriers responsible for the two blue emissions takes place in a kind of silicon excess defect centers (D centers, ·SiSi 3) at the surfaces of β-SiC crystallites, whereas the photogeneration of carriers partially occurs in the β-SiC crystallite cores. The obtained results are expected to have important applications in modern optoelectronic devices.