Higher-order nonlinear electromechanical effects in wurtzite GaN/AlN quantumdots

Abstract

As we demonstrated earlier, conventional mathematical models based on linearapproximations may be inadequate in the analysis of properties of low-dimensionalnanostructures and band structure calculations. In this work, a general three-dimensionalaxisymmetric coupled electromechanical model accounting for lattice mismatch,spontaneous polarization and higher-order nonlinear electrostriction effects has beenapplied to analyze properties of GaN/AlN quantum dots coupled with wetting layer. Thegeneralized model that accounts for five independent electrostriction coefficients has beensolved numerically via a finite-element implementation. The results, exemplified fortruncated conical GaN/AlN quantum dots, demonstrate that the effect of nonlinearelectrostriction in GaN/AlN nanoheterostructure quantum dots could be significant. Inparticular, the influence of nonlinear electromechanical effects on optoelectronic propertiesis highlighted by the results on band structure calculations based on a multiband effectivemass theory.