Laterally-current-injected light-emitting diodes based on nanocrystalline-Si/SiO2 superlattice

Laterally electrically-pumped Si light-emitting diodes (LEDs) based on truncated nanocrystalline-Si (nc-Si)/SiO2 quantum wells are fabricated with complementary-metal-semiconductor-oxide (CMOS) process. Visible electroluminescence (EL) can be observed under a reverse bias larger than ~6 V. The light emission would probably originate from the spontaneous hot-carrier relaxations within the conduction and the valance bands when the device is sufficiently reverse-biased. The EL spectral profile is found to be modulated by varying structure parameters of the interdigitated finger electrodes. Up to ~20 times EL intensity enhancement is achieved as compared to vertical-current-injection LED prepared using the same material system. Based on the lateral-current-injection scheme, a Si/SiO2 MQW LED with Fabry-Perot (FP) microcavity and an on-chip waveguided LED that emits at 1.55-µm are proposed.