Adsorption-controlled growth of La-doped BaSnO3 by molecular-beam epitaxy

TL;DR

This paper reports the growth of La-doped BaSnO3 films via molecular beam epitaxy in an adsorption-controlled regime, achieving high electron mobility and revealing defect-related mobility limitations.

Contribution

It demonstrates a novel growth method for La-doped BaSnO3 with high mobility and low defect density, advancing epitaxial film quality understanding.

Findings

Achieved 183 cm^2 V^-1 s^-1 mobility at room temperature

Observed low (BaO)2 shear fault density compared to other reports

Identified defects impacting electron mobility beyond threading dislocations

Abstract

Epitaxial La doped BaSnO3 films were grown in an adsorption controlled regime by molecular beam epitaxy, where the excess volatile SnOx desorbs from the film surface. A film grown on a (001) DyScO3 substrate exhibited a mobility of 183 cm^2 V^-1 s^-1 at room temperature and 400 cm^2 V^-1 s^-1 at 10 K, despite the high concentration (1.2x10^11 cm^-2) of threading dislocations present. In comparison to other reports, we observe a much lower concentration of (BaO)2 Ruddlesden Popper crystallographic shear faults. This suggests that in addition to threading dislocations that other defects possibly (BaO)2 crystallographic shear defects or point defects significantly reduce the electron mobility.