Preparation of one-dimensional single and multi-layered quantum wire structures by ultrafine deep mesa etching techniques

Abstract

We report on optimized holographic lithography and reactive ion etching processes to prepare by deep mesa etching techniques ultrafine structures with lateral dimensions of 200 nm to 550 nm in modulation doped AlGaAs/GaAs heterostructures and multi quantum well systems. These structures exhibit a one-dimensional (1D) electronic behaviour with discrete 1D subbands of typically 1 meV to 2 meV energy separation. The lateral width of the 1D electron channels is smaller than the geometrical width, indicating a lateral edge depletion region which, however, for an optimized process is only 100 nm on either side of the 1D wires.