The research at the Physical Electronics and nanotechnology group covers a broad range of research topics in materials and devices. Both experimental as well as theoretical research has been conducted. At present, the main research general topic is on the growth, characterization, modeling and device realization based on nano-structures on different substrates. The research can be divided as:
Growth of nanostructures and thin films:
We are mainly working on the growth and structural and optical characterization of nanostructures of ZnO and its compounds. The growth procedure is mainly three fold. We use the catalytic vapor liquid solid growth (VLS), the low temperature aqueous chemical growth (ACG) and recently we have started the metal organic chemical vapour deposition chamber to growth ZnO epitaxial film. Also, we are working on the fabrication of the graphene nanoribbons.
Here light emitting diodes, lasers and displays are being developed based on ZnO nanostructures on both crystalline as well as amorphous substrates. The device fabrication is followed by through electrical and optoelectrical characterization. Our aim is to develop high brightness white light emitting diodes utilizing the green emission band in ZnO beside the development of silicon compatible electrical pumped lasers. In addition, multi-color low voltage displays are recently added to the research interest in the group. The part of the research activity is of strategic nature as solid state lighting will rely in the near future on solid state devices to save power and for other environmental considerations.
The application of nanostructures as electrochemical sensors is another challenging area of research within our activity. We use nano-structures, at present, mainly ZnO nano-wires and nanotubes, to develop proto-type sensitive selective sensors that operate in small volumes of the analyte in question, and can perform real time analysis for specifically physiological species. An example of this is the intracellular electrochemical nanosensor developed recently. This is an intracellular electrochemical nanosensor that can accurately measure the pH, most important metal ions, glucose and cholesterol of the cell, and hence detect the health condition of the cell. We expect such a device can help in performing local detection and treatment. We are developing such device to later include an optical component to kill a specific cancerous cell after the detection.
ZnO with its excellent electro-mechanical coupling properties is also being realized in our research. Namely piezoelectricity based on ZnO nano-wires grown on different substrates is an active research area. After the careful growth of special vertical well aligned ZnO nano-wires, mechanical properties are being investigated using different techniques, among which nano-indentation has been used the most frequently. Critical force that a single nano-wire can withstand is carefully investigated to understand the mechanical applied force limits of our nano-wires before using it as piezoelectric components. This is then followed by the design of the electro-mechanical device based on the nano-wires. Indeed this is another challenging task. Our aim is develop a nano-generator which provides an efficiency of at least 30%.
Bose Einstein condensation of exciton-polaritons:
This project deals with partly theory/simulation and partly with experiments on the exciton polaritons and its collective phenomena in nanostructures as BEC condensation and superfluidity. Examples of problems which have been investigated or are under investigations are temperature effects, influence of external potential, number of particles, particle-particle interaction etc. Structures which are under investigations are wires, microcavities, photonic crystals etc.
Last updated: Fri May 28 08:52:34 CEST 2010