Polarization potentials in InGaN/GaN semiconductor quantum dots

The polarization potentials as functions of the wetting layer thickness and the In composition in InGaN/GaN semiconductor quantum dots are investigated using the theory of continuum elasticity based on a three-dimensional finite element method. The strain-induced potential is found to increase rapidly with increasing In composition. The potential is almost entirely contributed by the strain-induced piezoelectric polarization, irrespective of the In composition. The total potential at the boundary between the quantum dot and the barrier regions gradually increases with increasing wetting layer thickness. Hence, the optical properties are expected to depend highly on the wetting layer thickness.