Adsorption-controlled plasma-assisted molecular beam epitaxy of LaInO3 on DyScO3(110): Growth window, strain relaxation, and domain pattern

TL;DR

This study demonstrates the epitaxial growth of LaInO3 on DyScO3(110) substrates using plasma-assisted molecular beam epitaxy, analyzing growth conditions, strain relaxation, and domain structures, with implications for 2D electron gases.

Contribution

It provides a detailed characterization of LaInO3 growth on DyScO3(110), including growth window, strain relaxation, and domain patterns, advancing understanding of oxide heterostructures.

Findings

Growth window narrower than predicted by thermodynamics.

Critical thickness for strain relaxation is approximately 1 nm.

Epitaxial relationship confirmed by XRD and TEM, with orthorhombic domains.

Abstract

We report the growth of epitaxial LaInO3 on DyScO3(110) substrates by adsorption-controlled plasma-assisted molecular beam epitaxy (PA-MBE). The adsorption-controlled growth was monitored using line-of-sight quadrupole mass spectrometry. In a thermodynamics of MBE (TOMBE) diagram, the experimental growth window was found to be significantly narrower than the predicted one. We found the critical thickness for strain relaxation of the LaInO3 layer (lattice mismatch $\approx$ -4$\%$) to be of 1 nm using in-situ RHEED analysis. Substrate and film possess an orthorhombic crystal structure which can be approximated by a pseudo-cubic lattice. X-ray-diffraction (XRD) analysis revealed the pseudo-cube-on-pseudo-cube epitaxial relationship ofthe LaInO3 films to the DyScO3 substrates. This relation was confirmed by transmission electron microscopy (TEM), which further resolved the presence of rotational orthorhombic domains - the majority of which have coinciding c-axis with that of the substrate. Raman spectroscopy further confirmed the presence of a LaInO3 layer. Our findings open up the possibility for 2-dimensional electron gases at the MBE-grown heterointerface with BaSnO3.