High Mobility Cd3As2(112) on GaAs(001) Substrates Grown via Molecular Beam Epitaxy

The three-dimensional Dirac semimetal Cd₃As₂ exhibits ultrahigh electron mobilities that are attractive for optoelectronic devices. However, its strong propensity to grow in the (112) orientation limits the feasibility to epitaxially integrate it into semiconductor structures that are conventionally grown in the (001) orientation. Here, we demonstrate a route to epitaxially growing high mobility Cd₃As₂(112) layers on GaAs(001) substrates, opening up possibilities for device design. The (001) crystallographic orientation of the GaAs substrate is switched to the (111) orientation through a strain-driven process at a CdTe/GaAs interface, resulting in a CdTe(111) buffer layer on top of which Cd₃As₂ can be grown. Although the CdTe(111) buffer layer templates Cd₃As₂ in the (112) orientation, it is not sufficient for producing Cd₃As₂ with high electron mobility. We therefore demonstrate additional buffer layer design principles for realizing Cd₃As₂(112) epilayers with similar electron mobilities to those grown on lattice-mismatched III-V (111) substrates. Finally, we outline a pathway to use this approach to grow Cd₃As₂(112) epilayers on Si(001) substrates, further expanding the potential to integrate Cd₃As₂ into electronic devices.