Highly oriented EuO nanocrystalline films via reduction process - NIR optical response

TL;DR

This paper reports the fabrication of highly oriented EuO nanocrystalline films via a reduction process, demonstrating their optical properties in the near-infrared range and potential for optoelectronic applications.

Contribution

It introduces a simple reduction method to produce high-quality EuO films with controlled orientation and nanocrystalline structure for NIR optoelectronic use.

Findings

EuO films are nanocrystalline with 11 nm average crystallite size.

The films exhibit high transparency and a refractive index of 2.1 in the NIR.

A band-gap shift of 0.25 eV compared to bulk EuO was observed.

Abstract

Nanocrystalline textured EuO thin films are prepared by an oxygen loss process from a pure Eu2O3 bulk ceramic target through pulsed laser deposition in vacuum at room temperature. X-ray diffraction spectra evidence a well-defined diffraction peak corresponding to the EuO phase textured along the (110) direction. Analysis of the XRD peak profile indicates that the films are nanocrystalline (average crystallite size of 11 nm) with a compressive residual strain. The formation of stoichiometric EuO is further confirmed by a strong signal from Eu2+ in the X-ray photoelectron spectra. The complex refractive index in the near infrared has been determined by spectroscopic ellipsometry and shows that the EuO films have a high transparency (k < 10-3) and a refractive index of 2.1. A band-gap shift of 0.25 eV is found with respect to the EuO bulk. These films, deposited by an accessible and efficient method, open a new route to produce EuO films with optical quality, suitable for NIR optoelectronic components.