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Research Projects
Project: ZnO wide-band-gap semiconductors for optoelectronic devices
The research work focuses on the development of ZnO based wide band gap semiconductors such as ZnO and ZnMgO alloys. Studies included are thin film growth by pulsed laser deposition, optimization of process parameters, Quantum well heterostructures and p and n-type doping to fabricate pn junctions for LEDs and laser diodes.
Project: Electrical Field Effect and Phase Separation in CMR Manganites and Cuprates
In this work, field effect devices with CMR manganite or cuprate channels are fabricated with SrTiO3 or ferroelectric gates. The systematics of gate voltage induced modulation of channel conductance reflects electronic phase separation in these doped antiferromagnets.
Project: Spin Polarized Quasi Particle Injection in High Tc Cuprates
Hetrostructures of CMR and High Tc materials are made to examine the effects of the injection of spin polarized electrons in high Tc superconductors. Issues such as critical current suppression, Andreev reflection and bound states, zero bias cnductance peak (ZBCP) are addressed. X-ray Magnetic Circular Dichroism is employed to characterize the chemical and magnetic quality of the interfaces.
Plume generated by Excimer laser hitting on ceramic target. Pulsed Laser Deposition(PLD) is a fast way of making a variety of high quality thin films and hetero-structures.
Project: Femtosecond Optical Response of High Tc Superconductors
In this experiment femtosecond(fs) laser pulses of width ~100 fs. and repetition rate 10 khz onto a patterned 30 micon wide trnsmission line put in the form of a bridge of high Tc superconductor. The incoming photons break Cooper pairs and supress superconductivity. This will cause a change in the kinetic inductance of the bridge and is monitered using a digital sampling oscilliscope with a time resolution of 20 pico second. The change in the kinetic inductance has been studied as a function of laser power, sample temperature and individual photon energy. Existence of extremeiy sharp resonances are found for incident photon energy around 1.5 eV which support the idea of electronic phase separation in high Tc superconductors.
100 femto-second Ti: sphaire laser system.
Project: Study of wide band gap Zinc Oxide semiconductor
Due to its wide band gap (~3.3 eV at room temperature) and large exciton binding energy (60 meV), ZnO is a potential material for fabricating optoelectronic devices that operate in the blue and UV region. At CSR, UMCP we aim at improving the quality of pure and/ or various element doped ZnO thin films, exploring the possibility of integrating ZnO with Si and GaN, and developing prototype devices such as LEDs, LDs, photodetectors and optical memories
ZnO Based VCSEL with Dielectric DBR
Center for Superconductivity Research, University of Maryland, College Park, MD 20742-4111
Phone: 301.405.6129 Fax: 301.405.3779
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