How important is nonlinear piezoelectricity in wurtzite GaN/InN/GaN quantum disk-in-nanowire LED structures?
Numerical investigation is carried out to compare the effects of linear and nonlinear piezoelectric fields on the electronic and optical properties of recently-proposed wurtzite GaN/InN/GaN quantum disk-in-wire LED structures. The computational framework employs a combination of fully atomistic valence force-field molecular mechanics and 10-band \(sp^{3}s\)*-SO tight-binding electronic band-structure models, and accurately captures the interplay between the long-range electro-mechanical fields and the quantum atomicity in the device. In particular, to model piezoelectricity in the wurtzite lattice, four different polarization models (based on the experimental and ab initio coefficients) have been considered in increased order of accuracy. In contrast to recent studies on thin-film quantum well structures, simulation results obtained in this work show that the nonlinear (second-order) piezoelectric contribution has insignificant effects on the overall electronic and optical properties in reduced-dimensionality (nanoscale) disk-in-wire LED structures.
disk-in-wire led ingan non-linear piezoelectricity optical anisotropy atomistic simulation