4H-SiC samples irradiated with high energy protons were probed by low temperature photoluminescence (PL) and room temperature micro-Raman scattering spectroscopies. The quench of the near band-edge emission and the presence of a number of new sharp lines in the luminescence spectra of the proton-irradiated samples confirm the formation of various new defects. The changes of the line-shape and peak position of the longitudinal optical phonon-plasmon coupled (LOPC) mode in 4H-SiC are consistent with the decrease in the free carrier concentrations due to the introduction of carrier traps induced by the high energy proton irradiation. The estimated penetration depths for 6 and 8 MeV energy proton were 180 mu m and 300 mu m, respectively, which are in good agreement with the Monte Carlo numerical simulation results. At the 180 mu m and 300 mu m depths, the carrier concentrations were reduced by approximately 34% and 21%, respectively. (c) 2012 Elsevier B.V. All rights reserved.