Fabrication of coupled quantum dot arrays with a 100-150 nm period

This paper demonstrates a novel method for fabricating two-dimensional lateral surface superlattices. The technique involves etching a grid into a GaAs/GaAlAs modulation-doped heterostructure using a mask consisting of an array of 50-nm diam Ni/Au dots with a 100-150 nm period. Bias applied to a Schottky gate deposited over the structured surface varies the coupling strength between dots. The devices can be tuned to operate in the superlattice (weak and strong coupling) or the quantum dot (no coupling) regimes. Low-temperature characterization of the superlattices fabricated specifically for transport and capacitance measurements reveal novel magnetic field effects.