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	I. Superconducting devices

- Superconducting devices -
The high TC superconductor of Bi-family in which the conducting CuO2 planes are separated by insulating BiO-SrO layer give the phenomena of Josephson junction along the c-axis. The current is forced to flow along the array of intrinsic Josephson junction in the(00) c-axis. The 000 show a wide use in application, for instant large junctions can be used as a high frequency oscillator and submicron junctions can be used as voltage standards. Besides this, the submicron junctions have a wide range of application, for example electric field sensor and quantum current standards. A single crystal whisker of Bi2Sr2CaCu2O8+δ (Bi-2212) and Bi2Sr2Ca2Cu3O10+ δ (Bi—2223) can be used in the fabrication of nano-electronic devices utilizing intrinsic Josephson junction effect and related phenomena. We grow Bi-2212 and Bi-2223 single crystals whickers using solid state reaction method. We fabricate submicron devices by three-dimensional focused ion beam (3-D FIB) technique. The electrical characterizations of these devices are performed in close cycle refrigerators.
	II. Graphene and Graphene oxide based devices
Graphene (a single layer of carbon atoms) has significant potential for high-speed electronic applications. Particularly due to its high carrier mobility exceeding 200,000 cm2 V s-1 including a large critical current density ~ 2 × 108 A cm-2, it has attracted considerable interest as a potential new electronic material. In this lab, we do research on graphene and its electrical and electronic properties using field effect transistor devices patterning by lithographic technique. Graphene oxide (GO), consisting of hydrophilic oxygenated graphene sheets, now creates a lot of attention as it provides a route way to produce large quantities of graphene sheets in solution at low cost. In our lab, we do synthesis of graphene oxide using modified Hummers method. The electrical properties of GO thin films and thick films are being investigated in low temperature and also at high temperature. The further investigation on resistive memory switching is on progress.
	III. Research on Semiconducting Nano materials
Our current research focuses on the fundamental science in oxide semiconductor nanomaterial growth, properties characterization, fabrication of novel devices, and their applications in nanogenerators, gas-sensors, LED, nano FET, photocatalysis, and nanopiezotrnics. In research on semiconducting Nanomaterials The coupling of piezoelectric, photonic and seminconductor properties in ZnO nanowires enables novel applications as nanogenerators, piezoelectric gated diodes, piezoelectric field-effect transistors and strain sensors. Among them, nanogenerators have potential of converting ambient mechanical energy into electrical energy by just bending the nanowires (NW). when a ZnO NW is subject to a periodic mechanical stretching and releasing, the mechanical-electric coupling effect combined with gate effect of the Schottky contact at interface, results in alternating flow of charge in external circuit. This flow of charge/current can be used to derive the Nano devices.
	IV. Biological and environmental application of nanostructures
The research of this group focuses on the applications of nanomaterials for the following: antibacterial activity, cancer therapy, drug delivery systems and photocatalysis. Specific research fields include the growth and characterization of nanoparticles with various size, hybrid nanomaterials such as nanocomposite and core-shell nanostructures for above mentioned applications. FACS analysis for apoptosis induction, HL60 cells were treated with ZnO nanoparticles and then stained with FITC-annexin V. Shaded histograms represent cellular fluorescence of the control cells; open histograms represent the cellular fluorescence resulting from the specific binding of FITC-annexin V to apoptotic cells. (A) Cell control; (B) ZnO nanoparticles treated.