Investigations on the structural and optical properties of the swift heavy ion irradiated 6H [sbnd]SiC

Abstract

Single crystal 6H SiC wafers have been irradiated with 150 MeV Ag 12+ ions with fluences ranging from 1 × 10 11 to 1 × 10 13 ions/cm 2 at 300 K. The defect accumulation as a function of fluence was studied to determine changes in structural and optical properties. The variation in the fundamental Raman modes of the crystalline 6H SiC due to irradiation has been correlated with the disorder accumulation. The creation of defect states due to irradiation in the bandgap affects the blue-green photoluminescence emission in the irradiated samples. The UV–Visible absorption studies support the existence of defect states in the bandgap which is observed by the shift in the absorption edge towards the lower energy side with increasing fluence. Time Correlated Single Photon Counting photoluminescence decay results suggest that the existing defect states are radiative, exhibiting three lifetimes when irradiated with a fluence 5 × 10 11 ions/cm 2. The total number of lifetime components was reduced for a fluence 1 × 10 13 ions/cm 2 as the defect states produced increase the non-radiative defect centres. These results suggest that the accumulation of defects due to irradiation at fluences 5 × 10 11 and 1 × 10 13 ions/cm 2 are degenerate configurations which exhibit multiple lifetimes in photoluminescence studies. It is inferred that the optically active defect states influence the transition rate of charge carriers in this device material.