Luminescence properties of spark-processed GaP

We report the preparation of photoluminescing porous GaP using spark discharge in ambient air. The photoluminescence characteristics of spark-processed GaP (sp-GaP) have been studied at various temperatures. Further, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) studies have been performed. In addition to the luminescence peak of 2.21 and 1.79 eV of bulk GaP, the photoluminescence studies of sp-GaP at room temperature and low temperature revealed two additional emission bands in the UV (2.95 eV) and green (2.38 eV) region. XPS studies showed that the presence of oxides, predominantly gallates, on the surface of spark-processed GaP. The increased emission bands of sp-GaP compared with the bulk GaP is not associated with quantum confinement, but with the oxides on the surface of sp-GaP.