Nanoelectronics
Dramatic progress in novel electronic materials, including organic semiconductors, is opening up possibilities for flexible and large area electronics that can be produced in a very cost efficient way at low deposition temperatures and without immense vacuum chambers. Examples include pocket-size electronic maps, robotic skin sensors, rollable TVs, carpet-size solar cells and disposable chemical detectors, to name just a few. Organic semiconductors alone struggle to compete in applications where high switching speeds and high charge carrier mobility are required. Traditional inorganic materials such as silicon or germanium intrinsically are not flexible and require high temperature vacuum deposition processes. The challenge remains to develop high performance devices compatible with “wet” deposition processes such as printing and coating. The materials that can enable such devices are semiconductor nanoparticles in the form of nano-rods/nanowires, ribbons etc with a form factor such that the “particle” length substantially exceeds its “diameter”. Such materials can be processed from a solvent and also deposited over large area. An extended range of properties can also be obtained by combining properties of flexible organic “matrices” and high charge transporting inorganic nanoparticles.
The nanoelectronics sector of the NEC deals with fabrication and characterisation of electronic devices, mainly focusing on thin film transistors. Further, microwave research is also carried out within the sector, with primary focus being investigations into new planar circuits and antennas for use at millimetre-wave frequencies up to 220GHz. Recently, novel LTCC (low temperature co-fired ceramic) antenna structures have been developed at 150GHz, based on substrate integrated waveguides. These structures have provided a platform for the development of a new form of microwave integrated circuit using air-filled integrated waveguides. Measured results show very low levels of loss over a broad range of frequencies from 140 to 220GHz. As a complementary activity to the investigation of new circuit structures, the group is working on new methods for characterizing substrate and conductor materials at mm-wave frequencies.