The templates for pre-patterning of Si substrates for subsequent quantum dot growth by LEPECVD
were developed and successfully tested both in PMMA and by a lift-off
process. These patterns consist of dots or perpendicular lines which
will be transferred to the substrate as pits or trenches after reactive
ion etching. The patterns will be transferred to the substrates together
with the alignment marks for the second-level patterning of metal
electrodes. It is planned to address individual quantum dots and realize
single-electron and resonant tunneling transistors.
The research on low-dimensional systems has mainly been focused on field effect transistors, yet many conventional applications cannot be realized without diodes. For this reason one of the nanostructures we developed was a gate-controlled rectifier. The use of gate-induced junctions opens a route to reconfigurable electronic devices and provides valuable insight into the understanding of low-dimensional nanostructures. Standard diode was fabricated by patterning a SiGe modulation doped heterostructure grown by LEPECVD. A forward-to-reverse current ratio of more than 104 was obtained.