Theory of reduced built-in polarization field in nitride-based quantum dots

We use a surface integral method to show that the polarization potential in an InGaN/GaN quantum dot (QD) grown along the [0001] direction is strongly reduced compared to that in a quantum well (QW) of the same height. We use simple analytic expressions and different dot geometries to show that the reduction originates from two effects (i) the reduction in the QD [0001] surface area and (ii) strain redistributions in the QD system. The In composition can therefore be increased in a QD compared to a QW, enabling efficient recombination to longer wavelengths in InGaN QD structures.