IR-Absorption Spectra of Impurities in 6H-SiC

Abstract

ABSTRACTWe performed infrared absorption and reflectivity measurements on serverai 6H-SiC samples at variable temperatures between T=5K and T=300K. From the temperature dependence of the observed absorption lines we separated electronic from vibronic transitions. The electronic transitions are assumed to be due to transitions from the neutral nitrogen donor occupying the three different carbon lattice sites in 6H-SiC into excited states. We determined polarization and the oscillator strengths of these transitions. From the temperature dependence of the electronic transitions we determined the valley-orbit-splitting energy and we demonstrated the influence of compensation. For the different vibronic transitions we determined the Grüneisen constants.