Photon emission gain in Er doped Si light emitting diodes by impact excitation

TL;DR

This paper demonstrates photon emission gain in Er-doped silicon LEDs through impact excitation, achieving higher efficiency and paving the way for integrated silicon lasers and quantum light sources.

Contribution

It introduces a novel impact excitation mechanism in Er-doped silicon LEDs, enabling multiple photon emissions per electron and significantly improving efficiency.

Findings

Photon emission gain arises from impact excitation by a single electron.

Experimental IQE of 1.84% at 78 K, 20 times higher than room temperature.

Theoretical gain approximates the ratio of emission region width to electron mean free path.

Abstract

This work demonstrates photon emission gain, i.e., emission of multiple photons per injected electron, through impact excitation in Er-doped silicon light-emitting diodes (LEDs). Conventional methods for exciting Er ions in silicon suffer from low efficiency due to mismatched energy transfer between exciton recombination and Er excitation. Here, we propose a reverse-biased Si PN junction diode where ballistically accelerated electrons induce inelastic collisions with Er ions, enabling tunable excitation via electric field modulation. Theoretical modeling reveals that photon emission gain arises from multiple impact excitations by a single electron traversing the electroluminescence region, with the gain value approximating the ratio of emission region width to electron mean free path, i.e., G = Lex/l. Experimental results show an internal quantum efficiency (IQE) of 1.84% at 78 K, representing a 20-fold enhancement over room-temperature performance. This work provides a critical foundation for on-chip integration of silicon-based communication-band lasers and quantum light sources.