Raman and photoluminescence spectroscopy from n- and p-type 6H-SIC alpha-particle irradiated

We report optical properties of n-nitrogen and p-boron-type 6H-SiC alpha-particle irradiated at doses 10(12)-10(14)CM(-2). The back scattering Raman Spectroscopy (RS) from the reference samples reveals all the four first-order Raman active modes (1-RAMs) as well as all the 12th folded vibrational modes (FVMs) previously observed and tabulated. The irradiation at low doses induces several Raman optically active bands in the n- and p-type 6H-SiC. In order to identify the new modes we have derived some group-theoretical Raman selection rules (RSRs). Using the RSRs we have distinguished treatment-induced modes from the first-order RAM belonging to 6H-SiC. Moreover, by means of the RSRs we have made an attempt to identify the origins of some of the second-order phonons traditionally labelled as: a, b, h. Photoluminescence spectroscopy (PL) also monitors some new bands treatment induced. Some of them are temperature and laser power dependent. (c) 2005 Elsevier Ltd. All rights reserved.