Fabrication and optical properties of InGaAs/InP quantum wires and dots with strong lateral quantization effects

High-quality In0.53Ga0.47As/InP quantum wires and dots have been fabricated using high-voltage electron-beam lithography and wet chemical etching. Using poly(methyl-methacrylate) resist, gold lift-off, and wet chemical etching, dot structures with geometrical diameters down to approximately 30 nm and wires with lateral widths down to 16 nm have been obtained. The wire structures were studied optically by means of photoluminescence spertroscopy and show strong optical emission even for the smallest geometrical widths and without overgrowth. The weak decrease of the quantum efficiency with decreasing wire width indicates that there is no significant damage at the sidewalls of the wires, which is in contrast to previous studies on dry-etched structures. The photoluminescence energy of the In0.53Ga0.47As/InP wires is independent of the wire width down to approximately 60 nm. For smaller widths an increasing blue shift of the photoluminescence energy up to 60 meV is observed displaying a strong lateral quantization.