The formation of Er-oxide nanoclusters in SiO$_2$ thin films with excess Si

TL;DR

This study investigates the formation and growth of Er-oxide nanoclusters in SiO2 thin films with excess silicon, revealing initial Ostwald ripening followed by growth stagnation at a specific size.

Contribution

It provides detailed insights into the nucleation, distribution, and growth behavior of Er-oxide nanoclusters in SiO2, including the effects of electron beam exposure.

Findings

Nanoclusters form throughout the SiO2 layer with small Si and Er content.

Electron beam exposure causes nanocluster growth.

Growth follows Ostwald ripening then stagnates at 2.39 nm radius.

Abstract

The nucleation, distribution and composition of erbium embedded in a SiO$_2$-Si layer were studied with High Resolution Transmission Electron Microscopy (HRTEM), Electron Energy Loss Spectroscopy (EELS), Energy Filtered TEM (EFTEM), Scanning Transmission Electron Microscopy (STEM) and X-ray Photoelectron Spectroscopy (XPS). When the SiO$_2$ layer contains small amounts of Si and Er, nanoclusters of Er-oxide are formed throughout the whole layer. Exposure of the oxide to an electron beam with 1.56*10$^6$ electrons/nm$^2$/sec. causes nanocluster growth. Initially this growth matches the Ostwald ripening model, but eventually it stagnates at a constant nanocluster radius of 2.39 nm.