Abstract:

Transmission spectra of instinct and N doped 6H—SiC crystals in the visible and near infrared range were measured by using the UVVis spectrophotometer and infrared spectrum measurement system. Optical transmission spectra demonstrated that the 6H—SiC single crystal was transparent for visible and near infrared radiation. Compared with the 6H—SiC single crystal, it was also observed that  nitrogen doping could make the bandgap narrower, and the optical absorption of N doped SiC appeared in the visible and near infrared range. Also,  dispersion curves were obtained by the transmission spectra, and the refractive indices were analyzed using the dispersion equation in the transparent region. In addition,  spectra analysis showed that the absorption at 625nm corresponded to the free electron transition from the low energy level of band tailing induced by N doping to the high energy level in the conduction band, and the absorption of free carrier resulted in low transmission around 2500nm for nitrogen doped crystal.

Key words: 6H—SiC, transmission spectra, optical property