Capacitance–voltage characteristics of InAs/GaAs quantum dots embedded in a pn structure

We study the electronic states of self-organized InAs quantum dots embedded in a pn junction by means of capacitance–voltage (C–V) characteristics. A model based on the self-consistent solution of the Poisson equation and the drift-diffusion equations is proposed for calculating the capacitance. This model allows us to determine the energy levels of the quantum dot states and their inhomogeneous broadening from a comparison with experimental C–V data. Good quantitative agreement between predictions of the model and the low-frequency C–V characteristics is obtained.