Quantum wires and dots for optical studies

Abstract

InGaAs/InP quantum wires with widths down to 10 nm and dots with diameters down to 16 nm have been realized by electron beam lithography and wet chemical etching. Compared to previously investigated dry etching processes optically inactive sidewall layers can be avoided. The luminescence spectra of the quantum wires and dots show band edge shifts of up to about 80 meV due to the lateral quantization. Under high optical excitation several lateral states are populated. The lateral size dependence of the transition energies can be modelled quite accurately based on the measured sizes of the nanostructures. From the increase of the luminescence linewidths at low excitation in narrow quantum wires the typical size fluctuations in our structures are estimated to be on the order of ±2 nm.