Photoluminescence study of deep etched InGaAs/GaAs quantum wires and dots defined by low-voltage electron beam lithography

Abstract

Combining low-voltage electron beam lithography (EBL) and wet chemical etching, arrays of deep etched InGaAs/GaAs quantum wires with widths down to 15 nm and dots with minimum diameters of 27 nm have been fabricated. The application of low-voltage EBL strongly reduces the proximity effect during pattern exposure and allows the formation of very homogeneous nanostructure arrays. Low-excitation photoluminescence (PL) spectroscopy of both wires and dots reveals a structure size dependent blue shift of the emission lines up to 14 meV. This energy shift is caused by lateral confinement and shows a clear dependence on the structure dimensionality. The quantization is calculated with a simple model using only standard InGaAs/GaAs material parameters and the geometrical structure widths measured with a scanning electron microscope (SEM).