Within the framework of effective-mass approximation, the exciton states localized in cylindrical InGaN quantum dots (QDs) are investigated using a variational approach. The relationship between the exciton states and structural parameters of QDs with radius R and height L are studied in detail. The numerical results show that the exciton binding energy is sensitive to the ratio of R/L for a QD with a given volume. There is a maximum in the binding energy, where the electrons and holes are the most efficiently confined in the QDs with special structural parameters. The binding energy maximum can be obtained at about L = 1.7 nm for different QD volumes. The exciton binding energy and emission wavelength depend sensitively on structural parameters and the In content in the In x Ga 1-x N active layer. Our calculated emission wavelengths are in good agreement with experimental data.
The effects of polarization fields on exciton binding energy in GaN quantum dots
