Observations of conduction-band structure of 4H- and 6H-SiC

Abstract

Ballistic electron-emission spectroscopy (BEES) and photoluminescence are used to study conduction-band structure related transport properties of the 4H and 6H polytypes of SiC. A secondary energy threshold at 2.7 eV is observed in the BEES spectrum of 4H-SiC, in good agreement with a value of 2.8 eV deduced from reported ab initio calculations. The results from 6H-SiC, are suggested to be influenced by transport properties of other polytype inclusions, also supported by band-edge transitions evident in 6H-SiC photoluminescence spectra.