Multiband effective bond-orbital model for nitride semiconductors with wurtzite structure

TL;DR

This paper introduces a multiband empirical tight-binding model for wurtzite group-III-nitride semiconductors, accurately reproducing band structures and applied to bulk materials and quantum dots.

Contribution

It develops a minimal basis tight-binding model for nitride semiconductors that fits experimental and first-principle band data, including nanostructures.

Findings

Accurately reproduces band structures of GaN, AlN, InN.

Provides detailed parametrization for wurtzite semiconductors.

Demonstrates application to InN quantum dots embedded in GaN.

Abstract

A multiband empirical tight-binding model for group-III-nitride semiconductors with a wurtzite structure has been developed and applied to both bulk systems and embedded quantum dots. As a minimal basis set we assume one s-orbital and three p-orbitals, localized in the unit cell of the hexagonal Bravais lattice, from which one conduction band and three valence bands are formed. Non-vanishing matrix elements up to second nearest neighbors are taken into account. These matrix elements are determined so that the resulting tight-binding band structure reproduces the known Gamma-point parameters, which are also used in recent kp-treatments. Furthermore, the tight-binding band structure can also be fitted to the band energies at other special symmetry points of the Brillouin zone boundary, known from experiment or from first-principle calculations. In this paper, we describe details of the parametrization and present the resulting tight-binding band structures of bulk GaN, AlN, and InN with a wurtzite structure. As a first application to nanostructures, we present results for the single-particle electronic properties of lens-shaped InN quantum dots embedded in a GaN matrix.