Atomistic simulations of InGaN/GaN random alloy quantum well LEDs

In this work, a random distribution of Indium in a quantum well has been considered to study the effect on the energy gap of a GaN/InGaN/GaN LED device. Monte Carlo sampling technique has been used to generate hundreds of atomistic model structures of the device active region. In order to calculate pseudomorphic strain and internal deformations of the alloy, a multiscale method combining continuous media elasticity and atomistic valence force field models has been used. A multiphysic quantum/classical simulation coupling drift-diffusion with empirical tight-binding in order to compute the electron and hole states of the system has been performed. The reliable sp(3)d(5)s* parametrization has been used in the calculations of the eigenstates. We have found an energy gap difference of 50.9 meV for x(In) = 0.1 molar fraction between using virtual crystal approximation and a random distribution of In which increase with increasing Indium concentration. Moreover, electrons wave function seems to be more sensitive than holes due to Indium fluctuations [GRAPHICS] Electron and hole ground state spatial probability density (SPD) for a random QW sample (yellow: electron SPD, green: hole SPD. Red dots: In atoms, Gray dots: Ga atoms) (C) 201 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim