InGaAs/GaAs quantum wires defined by lateral top barrier modulation

We have fabricated buried InGaAs/GaAs quantum wires with widths down to 35 nm by using a novel and simple approach. The essential technological step is a selective wet etch process by which the material of the top GaAs barrier layer of a quantum well substrate is removed between quantum wire regions defined by high resolution electron beam lithography. The semiconductor vacuum boundary which locally replaces the energy band discontinuity of the quantum well induces a potential barrier which leads to a lateral potential well within the InGaAs layer. The wires show high emission intensity even for narrow wire widths and a significant shift of the emission to high energy for the smallest wires.