Competitive emission processes due to band-band and donor-acceptor transitions at the n-silicon carbide/electrolyte interface

Abstract

Electroluminescence (EL) due to band-band (423 nm) as well as donor-acceptor (565 nm) transitions was observed at n-SiC electrodes during the reduction of persulfate under pulsed cathodic polarization. The EL peak at 423 nm was obtained only when pulsed at cathodic potentials greater than the band gap of the semiconductor (E g ∼3.0 eV) but not under steady-state polarization. The EL decay characteristics, monitored at these two emission bands, indicate the competitive recombination processes during the hole injection of persulfate radicals into the valence band of the semiconductor. It was considered that the band-band emission comes from the bulk of the semiconductor