Electroluminescence and photoluminescence studies on carrier radiative and nonradiative recombinations in metal-oxide-silicon tunneling diodes

Abstract

Electroluminescence (EL) and photoluminescence (PL) measurements at silicon band gap energy from metal-oxide-semiconductor tunneling diodes on silicon have been carried out to study the carrier radiative recombination and nonradiative recombination near the silicon/silicon dioxide (Si/SiO2) interface. The temporal EL response indicates that the radiative recombination coefficient involved is as much as ten times greater than that of the bulk silicon. However, the nonradiative recombination is still the dominant carrier recombination process. Voltage-dependent PL shows that PL intensity increases with the bias voltage. This voltage dependence is attributed to the variations of nonradiative recombination rates due to the change of Fermi level with the bias voltage. The intensity of EL is found to be less temperature dependent than that of PL. The near-band-edge Fermi level for EL leads to the reduced and less thermal-active nonradiative recombination as compared to PL. This study shows that Fermi level near the Si/SiO2 interface strongly influences the nonradiative recombination rates and the resulting EL and PL intensities.