Experimental and theoretical study of the quantum-confined Stark effect in a single InGaN/GaN quantum dot under applied vertical electric field

We present a study of the effect of externally applied vertical electric field on the optical properties of single InGaN/GaN quantum dots via microphotoluminescence spectroscopy. This is achieved by incorporating the quantum dot layer in the intrinsic region of a p-i-n diode structure. We observe a large blue energy shift of similar to 60 meV, which is explained by the partial compensation of the internal piezoelectric field. The energy shift dependence on the applied field allows the determination of the vertical component of the permanent dipole and the polarizability. We also present theoretical modelling of our results based on atomistic semi-empirical tight-binding simulations. A good quantitative agreement between the experiment and the theory is found. (C) 2007 Elsevier Ltd. All rights reserved.