Efficient room-temperature light-emitters based on partly amorphised Ge quantum dots in crystalline Si

TL;DR

This paper presents a novel group-IV quantum dot light emitter compatible with silicon technology, demonstrating near-room-temperature photoluminescence and stimulated emission, advancing integrated silicon photonics.

Contribution

It introduces partly amorphised Ge quantum dots in silicon that exhibit quasi-direct bandgap and lasing-like behavior at room temperature, a significant improvement over previous SiGe nanostructures.

Findings

High photoluminescence stability up to room temperature

Observation of threshold behavior indicating stimulated emission

Potential for silicon-integrated light sources

Abstract

Semiconductor light emitters compatible with standard Si integration technology (SIT) are of particular interest for overcoming limitations in the operating speed of microelectronic devices 1-3. Light sources based on group-IV elements would be SIT compatible but suffer from the poor optoelectronic properties of bulk Si and Ge. Here, we demonstrate that epitaxially grown Ge quantum dots (QDs) in a fully coherent Si matrix show extraordinary optical properties if partially amorphised by Ge-ion bombardment (GIB). The GIB-QDs exhibit a quasi-direct-band gap and show, in contrast to conventional SiGe nanostructures, almost no thermal quenching of the photoluminescence (PL) up to room-temperature (RT). Microdisk resonators with embedded GIB-QDs exhibit threshold-behaviour and super-linear increase of the integrated PL-intensity (IPL) with increasing excitation power Pexc which indicates light amplification by stimulated emission in a fully SIT-compatible group-IV nano-system.