Nanomembranes are extremely thin, flexible and can be shaped into almost arbitrary 3D micro-architectures. For instance, strained nanomembrane devices with a large 2D footprint area can be released from the substrate surface and roll-up into their highly compact tubular counterparts. We demonstrated this principle for ultra-compact energy storage devices which may find use in passive and active elements in electronic circuitry. Rolled-up nanotech allows to smoothly contact molecular layers from the top yielding novel hybrid heterojunctions with applications in organic electronics and sensorics. Compressing rolled-up nanomembranes leads to the creation of hybrid superlattices composed of uniquely layered materials including single-crystalline semiconductors, metals, oxides and/or molecular layers. Such hybrid layer systems exhibit substantially reduced thermal transport properties and might be useful for future efficient thermoelectric materials.
The increase in heat production via the electrical current limits a further increase of signal velocity and miniaturization of semiconductor devices. There is no heat production in the ideal case of pure spin currents in magnetic semiconductors. We focus on the fabrication of diluted magnetic semiconductors by means of pulsed laser deposition or by magnetic ion implantation and short time annealing and on the manipulation and detection of spin currents in semiconductor spintronics devices with new functionalities.
Another approach towards the reduction of heat production is the use of the highly non-linear dynamic response of memristors to support both logic and memory simultaneously.
Materials Under Study
Semiconductor nanostructures (InAs/GaAs, Ge/Si), magnetic semiconductors (ZnO:(Mn,Co), In2O3:(Mn,Cr), GaAs:Mn, Ge:Mn, GaN:(Mn,Co)), novel spintronics devices (Tunnel magnetoresistance structure, Spin field effect transistor), memoxide nanostructures (VO2, BiFeO3).