Evidence of Silicon Band-Edge Emission Enhancement When Interfaced with SiO$_{2}$:Er Films

TL;DR

This study demonstrates a significant enhancement of silicon's infrared emission when interfaced with erbium-doped silica films, attributed to interface stresses that boost band-edge recombination, with potential implications for silicon photonics.

Contribution

It provides experimental evidence linking interface stress from sol-gel silica films to increased silicon band-edge emission, a novel insight into emission enhancement mechanisms.

Findings

Infrared emission increased nearly 100-fold with erbium-doped silica coating.

Maximum emission enhancement observed at 700°C annealing temperature.

Stress at the interface correlates with increased radiative recombination.

Abstract

Nearly two-orders of magnitude increase in room-temperature band-to-band (1.067 eV) infrared emission from crystalline silicon, coated with erbium-doped sol-gel films, have been achieved. Phonon-assisted band-to-band emission from coated and annealed p-Si is strongest for the sample annealed at 700$^{\circ}$C. In this paper, evidence of the origin of the emission band from the band edge recombination activities is established. Enhancement of radiative recombination of free carriers is reasoned by stresses at the interface due to the annealed sol-gel deposited silica. Comparative studies with other strained silicon samples are presented.