Avalanche-Mode Si Light-Emitting Transistor for Narrow-Band Emission Near 760 nm

We report an avalanche-mode light-emitting transistor (AMLET) in silicon (Si), based on a lateral bipolar junction, which emits light near 760 nm optical wavelength with a record low bandwidth of 38 nm. The AMLET, designed in a CMOS-compatible silicon-on-insulator (SOI) photonics platform, is optically confined within a $0.21 ~\mu \text{m}$ thick SOI layer, which forms a Fabry-Pérot (FP) resonator perpendicular to the Si surface. Light is emitted from the reverse biased emitter-base junction via phonon-assisted hot carrier recombination and, additionally, minority carriers are injected via the forward-biased Base-Collector junction. The combination of injection from collector terminal through a narrow base and FP optical resonance, yields a high optical power efficiency of $4.3\times 10^{-6}$ at ${V}_{\text {BC}}=0.8$ V and ${V}_{\text {EB}}=10$ V. Our work opens new possibilities in spectral-engineering of Si light-emitters, which could boost performance of all-Si optical interconnects and sensors.