Photoluminescence of ion-synthesized 9R-Si inclusions in SiO2/Si structure: effect of irradiation dose and oxide film thickness

TL;DR

This study investigates how ion irradiation dose and oxide film thickness influence the photoluminescence of 9R-Si phase inclusions in SiO2/Si structures, revealing optimal conditions for synthesizing optically active hexagonal silicon.

Contribution

It provides systematic insights into the effects of irradiation parameters and film thickness on 9R-Si phase formation and luminescence, advancing methods for optically active silicon nanostructures.

Findings

Photoluminescence at ~1240 nm linked to 9R-Si inclusions.

Luminescence intensity varies with oxide thickness and ion distribution.

Optimal irradiation conditions identified for 9R-Si synthesis.

Abstract

The study of hexagonal silicon polytypes attracts special attention due to their unique physical properties compared to the traditional cubic phase of Si. Thus, for some hexagonal phases, a significant improvement in the emission properties has been demonstrated. In this work, the luminescent properties of SiO2/Si structures irradiated with Kr+ ions at different doses and annealed at 800 {\deg}C have been systematically investigated. For such structures, a photoluminescence line at ~ 1240 nm is observed and associated with the formation of hexagonal 9R-Si phase inclusions. It is found that the variation in the thickness of oxide film and the relative position of ion distribution profile and film / substrate interface leads to a regular change in the luminescence intensity. The nature of the observed dependencies is discussed as related to the interplay between the desirable 3C-Si -> 9R-Si structural transition and generation of nonradiative defects. The revealed regularities suggest optimal ion irradiation conditions for synthesis of optically active 9R-Si phase in diamond-like silicon.