Cr2O3 thin films grown at room temperature by low pressure laser chemical vapour deposition

TL;DR

This paper demonstrates the room-temperature growth of pure Cr2O3 thin films on sapphire substrates using low pressure laser chemical vapour deposition, highlighting its potential for selective area and sensitive material applications.

Contribution

It introduces a novel low pressure LCVD method for growing Cr2O3 films at room temperature with controlled microstructure and deposition rates.

Findings

Polycrystalline Cr2O3 films achieved with specific laser fluence and gas ratios.

Films exhibit high particle density with lognormal size distribution.

Deposition rate of 0.1 nm/s and mean particle size of 1.85 μm.

Abstract

Chromia (Cr2O3) has been extensively explored for the purpose of developing widespread industrial applications, owing to the convergence of a variety of mechanical, physical and chemical properties in one single oxide material. Various methods have been used for large area synthesis of Cr2O3 films. However, for selective area growth and growth on thermally sensitive materials, laser-assisted chemical vapour deposition (LCVD) can be applied advantageously. Here we report on the growth of single layers of pure Cr2O3 onto sapphire substrates at room temperature by low pressure photolytic LCVD, using UV laser radiation and Cr(CO)6 as chromium precursor. The feasibility of the LCVD technique to access selective area deposition of chromia thin films is demonstrated. Best results were obtained for a laser fluence of 120 mJ cm-2 and a partial pressure ratio of O2 to Cr(CO)6 of 1.0. Samples grown with these experimental parameters are polycrystalline and their microstructure is characterised by a high density of particles whose size follows a lognormal distribution. Deposition rates of 0.1 nm s-1 and mean particle sizes of 1.85 {\mu}m were measured for these films.