Luminescence properties of spark-processed SiC

Abstract

The photoluminescence (PL) properties of spark-processed SiC (sp-SiC) have been studied at various temperatures. Furthermore, scanning electron micrographs (SEM), X-ray diffraction (XRD) measurements, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy have been applied. The luminescence properties of sp-SiC are quite different from unspark-treated reference 6 H SiC. Specifically, the PL intensities of sp-SiC are at least two orders of magnitude larger than the reference SiC. Furthermore, the room temperature PL spectrum of sp-SiC exhibits two luminescence bands peaking at 3.18 eV, which are considerably blue shifted from SiC band gap of 2.9 and 2.43 eV. However, these two luminescence bands show an unusual red-shift of PL peak energies with decreasing temperature. Raman spectroscopy studies of sp-SiC display the emergence of a crystalline Si vibrational mode, whereas vibrational modes associated with 6H SiC are completely annihilated. XRD analysis exhibits the formation of polycrystalline Si after spark processing. Vibrational modes obtained from FTIR for sp-SiC are mainly composed of Si–O modes with some OH vibration. The results of low temperature PL studies, FTIR, XRD, XPS and Raman spectroscopy demonstrate that the luminescence properties of sp-SiC are similar to spark-processed Si.