01/2011-06/2011
Under Dr. Konstantin Ilin and Dipl.-Ing. Johannes Maximilian Meckbach at Karlsruhe Institute of Technology-Institute of Micro- and Nanoelectronic Systems, Germany.
My motivation was to develop integrated THz receivers based on the trilayers. Prior to my work, studies were done on Nb/AlOx/Nb trilayers http://arxiv.org/abs/1009.0167. Josephson Junctions based on NbN/AlN/NbN trilayers are the elements of choice since they have considerably higher gap voltage as compared to JJs based on Nb/AlOx/Nb.
I worked in a 2nd generation DC Reactive Magnetron Sputtering System used for the the deposition of Nb and NbN and consecutively in a newly constructed 3rd generation DC Reactive Magnetron Sputtering System used for the deposition of Nb, NbN, Al and AlN in-situ. I preconditioned the new system and optimized the deposition of Nb, NbN, Al, AlN and multilayers concerning the epitaxial growth and critical temperature (Tc) of Nb and NbN. AlN is deposited with deposition parameters such that there is a lattice match with NbN. The parameters optimized for deposition in the chamber are partial pressures of Ar, N2 and total pressures, deposition temperature and the discharge power.
Measurements of Tc of the films are done using a four point measurement technique. The chips are wire bonded with Al wires on the chip holder. They are cryogenically cooled and the resistances are measured during the process. To measure the thicknesses of the films they are subjected to spin coating, photolithography and developing in the clean room. Subsequently, they are etched in the Reactive Ion Etching System with CF4 / O2 for Nb and SF6 / O2 for NbN. The thickness of the etched stripes are measured in the profilometer.
07/2010-08/2010
Under Prof. Peter Haenggi, Dipl.-Phys. Fei Zhan and Dr. Sebastian Deffner at Augsburg University, Germany.
Analysis is done on the sequential tunneling of electrons in a single molecule. The rate equations derived from the Hamiltonian are solved numerically in FORTRAN 77. The Franck-Condon Blockade is observed in strong electron-phonon coupling regime.
Presented in technical festival 'Radiance' at Indian Institute of Technology, Bombay.
The project is a proposal for a new non-conventional source of energy, i.e., lightning current. Three machines have been described which utilize lightning current for power generation through the principle of electromagnetic induction. The proposed machines can attract cloud-ground lightning by placing Early Streamer Emission (ESE) on top of them. The path of lightning is used for power generation to be stored in particular batteries. The machines must be installed at areas with high keraunic levels.