Band Alignment of the CuGaS₂Chalcopyrite Interfaces Studied by First-Principles Calculations

Abstract

The valence and conduction band offsets for both polar and nonpolar CuGaS2/CuAlSe2 and CuGaS2/ZnSe interfaces were studied here by the state-of-the-art first-principles calculations. Using the hybrid functional calculations, we show that the CuGaS2/CuAlSe2 and CuGaS2/ZnSe heterostructures in all interfaces form type II band alignment. The difference of valence and conduction band offsets is mainly due to lattice mismatch, generating stress in the interface and affecting the electronic properties of each material; meanwhile, the polarity configuration does not play an important role in these values. From the local density of states and the charge density, we can determine how the nature of the band alignments changes when the semiconductor conforms to each interface. This allows us to localize the electrons and holes at different sites of the interface.

Electronic Structure of InAs and InSb Surfaces: Density Functional Theory and Angle‐Resolved Photoemission Spectroscopy

“…The interface configuration may give rise to (desirable or undesirable) interface states, alter the band bending and band alignment, or affect the magnitude of the proximity-induced gap and spin-orbit coupling. [48][49][50] A deeper understanding of the relation between the structure and electronic properties of InX hybrid interfaces could advance the synthesis of precisely controlled interfaces with tunable properties.…”

Validation of Density Functional Theory Methods for Predicting the Optical Properties of Cu-Based Multinary Chalcogenide Semiconductors

“…To gain a deep understanding of the distinctive physical properties, it is critical to obtain an accurate description of the electronic structures of copper chalcogenide semiconductors, especially the information about band gap and band structure topology. Correspondingly, theoretical investigations on the electronic structures of Cu chalcogenides have attracted increasing interest in the past two decades. − However, the presence of strongly localized d electrons of Cu atoms leads to that the density functional theory (DFT) calculations within the local density approximation (LDA) and the generalized gradient approximation (GGA) are usually difficult to accurately describe the electronic structures of Cu-based multinary semiconductors, including the substantial underestimation of the band gap or the wrong prediction of energy band ordering. Even by using the DFT plus the Hubbard U correction (DFT + U ) approach that has been widely used in first-principles studies for strongly correlated systems, the calculated results still deviate obviously from the experimental measurements, although the prediction of the band gaps has been improved .…”

“…In the current paper, various optical responses of 16 typical Cu-containing multinary chalcogenide semiconductors have been studied systematically. We aim at finding an efficient DFT approach to obtain sufficiently accurate optical properties of Cu-based chalcogenide materials, in which five common DFT methods used for the investigations of the electronic structures and physical properties of these compounds have been considered, including the PBE, − PBE + U , − hybrid HSE06, − mBJ, ,, and mBJ + U methods . Using different theoretical approaches, we first particularly focus on ternary Cu-based semiconductors with the chalcopyrite structure whose linear optical susceptibilities have been well studied in experiments. − After careful comparisons of the calculated results with experimentally measured optical constants, it indicates that the mBJ + U approach can yield optical properties in better agreement with experimental data than other DFT methods.…”

Electronic structure of InAs and InSb surfaces: density functional theory and angle-resolved photoemission spectroscopy

“…Changes in the structure of the interface at the atomic scale affect the electronic properties. Indeed, the interface configuration may give rise to (desirable or undesirable) interface states, alter the band bending and band alignment, or affect the magnitude of the proximity-induced gap and spin-orbit coupling [48][49][50]. A deeper understanding of the relation between the structure and electronic properties of InX hybrid interfaces could advance the synthesis of precisely controlled interfaces with tunable properties.…”