Microstructure fabrication and transport through quantum dots

Abstract

We report the microfabrication techniques used to produce devices which study electronic transport through quantum dots. Molecular-beam epitaxy, electron-beam lithography, and reactive ion etching have been utilized in this effort. The minimum physical lateral size of the dots reported here is 0.1×0.2 μm. Transport shows some degradation in I–V characteristics with respect to much larger resonant tunneling diodes. Current densities observed suggest the electrical size of diodes is smaller than the physical size. A surface depletion region of 500 Å may account for this effect. Telegraph noise is observed as a result of single electron trapping in the structure. No clear evidence of lateral quantization has been observed.