Room temperature blue light emission from ECR-CVD deposited nano-crystalline SiC

In this paper, we will show some recent data on the room temperature blue light emission from SiC nano-crystallites. We deposited thin films on silicon substrates with an electron cyclotron resonance plasma enhanced chemical vapor deposition reactor (ECR-CVD). Films were deposited at 850°C and with several carbon concentrations near stoichiometry. The films are poly-crystalline and X-ray diffraction proves the presence of both the 3C and 6H polytypes. Transmission electron microscopy reveals a distribution of grain size between 1 and 10 nm. Infrared absorption spectroscopy in the region of SiH and CH bonds show no absorption band. Raman spectroscopy shows that no carbon clustering is present in the stoichiometric sample. otoluminescence has been measured at temperatures between 100 and 300 K. It consists of a relatively broad band centered around 450 nm and a second narrow band at 400 nm in the near stoichiometric samples. From the effect of thermal annealing and of light-induced defect creation, together with the temperature dependence, we attribute these emission bands to surface states and to band-to-band recombination, respectively.