Identification of vacancy defects in a thin film perovskite oxide

TL;DR

This study uses positron annihilation lifetime measurements to identify and analyze vacancy defects in thin film SrTiO3, revealing the distribution and nature of these defects across the film.

Contribution

It introduces a method to detect and characterize vacancy defects in thin film perovskite oxides using variable energy positron annihilation lifetime measurements.

Findings

Sr vacancy related defects are the main positron traps.

Vacancy defects are uniformly distributed except near the surface.

Surface layer shows increased large open-volume defects.

Abstract

Vacancy defects in thin film laser ablated SrTiO3 on SrTiO3 were identified using variable energy positron annihilation lifetime measurements. Strontium vacancy related defects were the dominant positron traps and, apart from in the top ~ 50 nm, were found to be uniformly distributed. The surface layer showed an increase in annihilation from larger open-volume defects, large vacancy clusters or nanovoids.