Confined energy states in quantum dots detected by a resonant differential capacitance method

Abstract

A novel method is demonstrated for revealing the presence of confined energy states in quantum dots. The samples used are Schottky diodes with quantum dots inserted in a plane inside its depletion region. By measuring the voltage derivative of the differential diode capacitance and plotting the data as contour diagrams on a voltage versus temperature plane, the confined charge carrier states are visualized as peaks. To confirm this interpretation, experimental data are compared with theory based on statistics earlier used for understanding data from deep level transient spectroscopy on the same type of samples.