Chemical trends of stability and band alignment of lattice-matched II-VI/III-V semiconductor interfaces

Abstract

Using first-principles density functional theory (DFT) method, we systematically investigate the structural and electronic properties of heterovalent interfaces of the lattice-matched II-VI/III-V semiconductors, i.e. ZnTe/GaSb, ZnSe/GaAs, ZnS/GaP and ZnO/GaN. We find that independent of the orientations, the heterovalent superlattices with period n = 6 are energetically more favorable to form nonpolar interfaces. For the [001] interface, the stable nonpolar interfaces are formed by mixing 50% group III with 50% group II atoms or by mixing 50% group V with 50% group VI atoms; For the [111] nonpolar interfaces, the mixing are 25% group III (II) and 75% group II (III) atoms or 25% group V (VI) and 75% group VI (V) atoms. For all the nonpolar interfaces, the [110] interface has the lowest interfacial energy because it has the minimum number of II-V or III-VI "wrong bonds" per unit interfacial area. The interfacial energy increases when the atomic number of the elements decreases, except for the ZnO/GaN system. The band alignment between the II-VI and III-V compounds are drastically different whether they have a mixed-cation or mixed-anion interfaces, but the averaged values are nearly independent of the orientations. Similarly, other than ZnO/GaN, the valence band offsets also increase as the atomic number of the elements decreases. The abnormal trends in interfacial energy and band alignment for ZnO/GaN are primarily attributed to the very short bond lengths in this system. The underlying physics behind these trends are explained.

Analysis of electrostatic stability and ordering in quaternary perovskite solid solutions

“…The influence of the local non-null charge in the interfaces is more significant when the thickness of the layers increases, since for thin layers (n = 1), (111) superlattices have lower mixing enthalpies than the (110) ones. A very similar result was found by Deng et al in (III,V)/(II,VI) semiconductor superlattices [51,52]. It is important to point out that we only considered in this study the regular stacking of planes in the perovskite structure.…”

Interfacial Oxidation and Photoluminescence of InP-Based Core/Shell Quantum Dots

“…Focusing in first instance on the abrupt interface, a point that is made in the literature is that the GaAs/ZnSe boundary can be made either through Ga-Se or As-Zn contacts. 27 Compensation is possible through mixed interfaces that involve, for example, mixed (Ga,Zn) or (As,Se) planes, 28 or vacancies. 29 Importantly, the atomistic structure of the interface has a huge impact on band offsets, and can lead to a density of states with metallic character.…”

Enhanced visible light absorption in ZnO/GaN heterostructured nanofilms

“…Since electronic properties of ZnO/GaN heterostructures are strongly dependent on their hetero-interfaces [13][14][15][16][17], two types of non-polar ZnO/GaN heterostructured nanofilms with wurtzite structures, that is,…”

“…And thus, the distributions of valence band maximum (VBM) and conduction band minimum (CBM) (or photo-generated electrons and holes) mix together in some certain spaces, which results in a low efficient utilization of the solar energy. In addition, numerous studies have suggested that the wurtzite ZnO and GaN could form various heterojunction interfaces with remarkable separated distribution of electrons and holes [13][14][15][16][17][18]. Due to the effects of type-II band offset [13,14], the ZnO/GaN heterostructured semiconductors present narrow band gaps in the visible-light region and can serve as potential photocatalysts [16,17].…”