Polarization strategies to improve the emission of Si-based light sources emitting at 1.55μm

► We study the electroluminescence of LPCVD SiOx layers doped or not with Er ions. ► Direct current and pulsed voltage polarization have been used to compare the EL. ► Annealing treatment is correlated with the visible EL improvement in pulsed voltage. ► The improvement is ascribed to the lack of auger processes at the voltage switch off. ► The infrared EL in Er doped devices does not improve under pulsed voltage. We present a electroluminescence (EL) study of the Si-rich silicon oxide (SRSO) LEDs with and without Er3+ ions under different polarization schemes: direct current (DC) and pulsed voltage (PV). The power efficiency of the devices and their main optical limitations are presented. We show that under PV polarization scheme, the devices achieve one order of magnitude superior performance in comparison with DC. Time-resolved measurements have shown that this enhancement is met only for active layers in which annealing temperature is high enough (>1000°C) for silicon nanocrystal (Si-nc) formation. Modeling of the system with rate equations has been done and excitation cross-sections for both Si-nc and Er3+ ions have been extracted.