Efficient Silicon Light-Emitting-Diodes with a p-Si/Ultrathin SiO2/n-Si Structure

Abstract

We report the efficient enhancement of light emission from silicon crystal by covering the silicon surface with an ultrathin (several nm) SiO2 layer. The photoluminescence of Si band edge emission (1.14 μm band) at room temperature is enhanced by two orders of magnitude. Compared with a p-Si/n-Si diode, light emission from a p-Si/SiO2/n-Si diode by current injection via direct tunneling is enhanced by more than 3 orders of magnitude. The light-emission enhancement is attributed to the diminishment of nonradiation recombination at the surface/interface and to the space confinement of the carrier recombination. The simple structure and low operating bias (approximately 1 volt) of our light emitting diodes supply a new choice for realizing efficient current injection light source in silicon compatible with conventional ULSI technology.