Interface structure and luminescence properties of epitaxial PbSe films on InAs(111)A

Abstract

Epitaxial heterostructures of narrow-gap IV-VI and III-V semiconductors offer a platform for new electronics and mid-infrared photonics. Stark dissimilarities in the bonding and the crystal structure between the rocksalt IV–VIs and the zincblende III–Vs, however, mandate the development of nucleation and growth protocols to reliably prepare high-quality heterostructures. In this work, we demonstrate a route to single crystal (111)-oriented PbSe epitaxial films on nearly lattice-matched InAs (111)A templates. Without this technique, the high-energy heterovalent interface readily produces two populations of PbSe grains that are rotated 180° in-plane with respect to each other, separated by rotational twin boundaries. We find that a high-temperature surface treatment with the PbSe flux extinguishes one of these interfacial stackings, resulting in single-crystalline films with interfaces that are mediated by a monolayer of distorted PbSe. While very thin PbSe-on-InAs films do not emit light, hinting toward a type-III band alignment, we see strong room temperature photoluminescence from a 1.5 μm thick film with a minority carrier lifetime of 20 ns at low-excitation conditions and bimolecular recombination at high excitation conditions, respectively, even with threading dislocation densities exceeding 108 cm−2. We also note near-complete strain relaxation in these films despite large thermal expansion mismatch to the substrate, with dislocations gliding to relieve strain even at cryogenic temperatures. These results bring to light the exceptional properties of IV-VI semiconductors and the new IV-VI/III-V interfaces for a range of applications in optoelectronics.

Optimization of the Growth of the Van der Waals Materials Bi2Se3 and (Bi0.5In0.5)2Se3 by Molecular Beam Epitaxy

“…The fourth strategy we tried is predose treatment of the substrate. It has been shown that by exposing the substrate to the material flux above the thermal decomposition temperature, single crystal (111)-oriented PbSe can be epitaxially grown on nearly lattice-matched InAs (111) A templates . Twin formation has been suppressed by a predose of the epitaxy material.…”

“…It has been shown that by exposing the substrate to the material flux above the thermal decomposition temperature, single crystal (111)-oriented PbSe can be epitaxially grown on nearly lattice-matched InAs (111) A templates. 71 Twin formation has been suppressed by a predose of the epitaxy material. A similar method of predosing the substrate with Bi 2 Se 3 has been tried on sapphire: a bismuth predose of 2 min at a low temperature is used followed by growth of a buffer layer of Bi 2 Se 3 , which is then re-evaporated in a flash heat up process.…”

Scale-dependent optimized homoepitaxy of InAs(111)A

“…3 Furthermore, epitaxial heterostructures of narrow-gap IV-VI and III-V semiconductors are a promising candidate for mid-infrared photonics, where the main benefits are the lattice constant matching, mechanical strength, chemical stability, and thermal conductivity as compared to the currently used substrates. 4 InAs is also the compound semiconductor of choice for building a hybrid semiconductor-superconductor based topological quantum bit, due to its unique combination of electronic properties such as e.g. large spin-orbit interaction and a narrow direct bandgap.…”

Scale-Dependent Optimized Homoepitaxy of InAs(111)A

“…3 Furthermore, epitaxial heterostructures of narrow-gap IV−VI and III−V semiconductors are a promising candidate for midinfrared photonics, where the main benefits are the lattice constant matching, mechanical strength, chemical stability, and thermal conductivity as compared to the currently used substrates. 4 InAs is also the compound semiconductor of choice for building a hybrid semiconductor−superconductorbased topological quantum bit, due to its unique combination of electronic properties such as, e.g., large spin−orbit interaction and a narrow direct bandgap. 5 InAs(111) forms a low strain interface with GaSb and AlSb, other technologically relevant III−V compound semiconductors, as well as several II−VI compound semiconductors.…”