Defects in Cd3As2 Epilayers Via Molecular Beam Epitaxy and Strategies for Reducing Them

TL;DR

This paper investigates the types of defects in Cd3As2 epilayers grown by molecular beam epitaxy and explores strategies to reduce these defects, thereby enhancing electron mobility for topological semimetal applications.

Contribution

It introduces defect suppression techniques in Cd3As2 epitaxial growth, achieving high electron mobility and providing insights into defect impact on material quality.

Findings

Defects like dislocations, twins, and point defects affect electron mobility.

Combining defect suppression methods increases room-temperature electron mobility to over 15,000 cm2/V-s.

Use of lattice-matched buffer layers and broadband illumination effectively reduces defects.

Abstract

Molecular beam epitaxy offers an exciting avenue for investigating the behavior of topological semimetal Cd3As2, by providing routes for doping, alloying, strain engineering, and heterostructure formation. To date, however, minimal exploration has been devoted to the impact of defects that are incorporated into epilayers due to contraints imposed by the substrate and narrow growth window. Here, we use a combination of lattice-matched ZnxCd1-xTe buffer layers, miscut substrates and broadband illumination to study how dislocations, twins and point defects influence the electron mobility of Cd3As2. A combination of defect suppression approaches produces Cd3As2 epilayers with electron mobilities upwards of 15,000 cm2/V-s at room temperature.