Abstract

We have derived consistent sets of band parameters (band gaps, crystal field splittings, band-gap deformation potentials, effective masses, and Luttinger and ${E}_{P}$ parameters) for AlN, GaN, and InN in the zinc-blende and wurtzite phases employing many-body perturbation theory in the ${G}_{0}{W}_{0}$ approximation. The ${G}_{0}{W}_{0}$ method has been combined with density-functional theory (DFT) calculations in the exact-exchange optimized effective potential approach to overcome the limitations of local-density or gradient-corrected DFT functionals. The band structures in the vicinity of the $\ensuremath{\Gamma}$ point have been used to directly parametrize a $4\ifmmode\times\else\texttimes\fi{}4$ $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ Hamiltonian to capture nonparabolicities in the conduction bands and the more complex valence-band structure of the wurtzite phases. We demonstrate that the band parameters derived in this fashion are in very good agreement with the available experimental data and provide reliable predictions for all parameters, which have not been determined experimentally so far.

Highlights

  • The group-III nitrides AlN, GaN, and InN and their alloys have become an important and versatile class of semiconductor materials, in particular, for use in optoelectronic devices and high-power microwave transistors

  • We demonstrate that the band parameters derived in this fashion are in very good agreement with the available experimental data and provide reliable predictions for all parameters, which have not been determined experimentally so far

  • We have previously shown that the OEPx+ G0W0 approach provides an accurate description of the quasiparticle band structure for GaN, InN, and II-VI compounds.[23,34,35]

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Summary

INTRODUCTION

The group-III nitrides AlN, GaN, and InN and their alloys have become an important and versatile class of semiconductor materials, in particular, for use in optoelectronic devices and high-power microwave transistors. We have previously shown that the OEPx+ G0W0 approach provides an accurate description of the quasiparticle band structure for GaN, InN, and II-VI compounds.[23,34,35] The quasiparticle band structure in the vicinity of the ⌫ point is used to parametrize a 4 ϫ 4 k · p Hamiltonian to determine band-dispersion parameters, such as effective masses, Luttinger parameters, etc This allows us to take the nonparabolicity of the conduction band, which is pronounced in InN,[29,36] and the more complex valence-band structure of the wurtzite phases into account properly.

GW based on exact-exchange density functional theory
Computational parameters
Lattice parameters
Band gaps
Crystal-field splitting
Band-gap deformation potentials
BAND-DISPERSION PARAMETERS
Computational details
Comparison to experimental values
Other parameter sets
CONCLUSION

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