The Role of Colloidal Er-Doped SiO₂ Thin-Film Interfaced with Czochralski Silicon on Enhanced Bandgap Emission for Optoelectronic Applications

Colloidal silica bulk glass and coatings have been studied extensively for many years. In this work we report a new optoelectronic phenomenon introduced by interfacing Er-doped sol-gel silica on Czochralski silicon (Cz-Si). The discovery is noteworthy on two aspects: (i) strong enhancement of bandgap emission, and (ii) modeling the observed luminescence spectra reveals strong dominance of correlated electron-hole (e-h) radiative recombination. Colloidal interfacial reactions with Cz-Si surface are known to introduce random interfacial strain fields that favors the radiative recombination interactions. The modeling of the room-temperature photoluminescence spectra exhibit attenuates a strong attenuation of the shorter tail of the emission spectra; thus, amplifying the excitonic e-h. The presentation will also include a comparative study of the bandgap emission of thermally oxidized Cz-Si with the colloidal prepared spin-coated silica on Cz-Si to highlight the discovery.