Nanopatterning of semiconductor substrates

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.

Nanoelectronics in semiconductor heterostructures

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.