# Enhancing SiGeSn nanocrystals SWIR photosensing by high passivation in nanocrystalline HfO2 matrix

## TL;DR

This paper explores how SiGeSn nanocrystals embedded in HfO2 improve short-wavelength infrared photosensitivity for optoelectronic devices.

## Contribution

The study introduces a novel method of embedding SiGeSn nanocrystals in a nanocrystalline HfO2 matrix for enhanced SWIR photosensing.

## Key findings

- SiGeSn nanocrystals in HfO2 show SWIR photosensitivity up to 2000 nm.
- HfO2 matrix provides better passivation and thermal stability compared to SiO2.
- RTA enables surface passivation of nanocrystals, enhancing performance.

## Abstract

SiGeSn nanocrystals (NCs) in oxides are of considerable interest for photo-effect applications due to the fine-tuning of the optical bandgap by quantum confinement in NCs. We present a detailed study regarding the silicon germanium tin (SiGeSn) NCs embedded in a nanocrystalline hafnium oxide (HfO2) matrix fabricated by using magnetron co-sputtering deposition at room temperature and rapid thermal annealing (RTA). The NCs were formed at temperatures in the range of 500–800 °C. RTA was performed to obtain SiGeSn NCs with surfaces passivated by the embedding HfO2 matrix. The formation of NCs and β-Sn segregation were discussed in relation to the deposition and processing conditions by employing HRTEM, XRD and Raman spectroscopy studies. The spectral photosensitivity exhibited up to 2000 nm in short-wavelength infrared (SWIR) depending on the Sn composition was obtained. Comparing to similar results on GeSn NCs in SiO2 matrix, the addition of Si offers a better thermal stability of SiGeSn NCs, while the use of HfO2 matrix results in better passivation of NCs increasing the SWIR photosensitivity at room temperature. These results suggest that SiGeSn NCs embedded in an HfO2 matrix are a promising material for SWIR optoelectronic devices.