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photoresponse
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Quantum Dot Infrared Photodetector
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
Conventionally all objects radiate most of its energy in the from of infrared waves, therefore, infrared photodetectors for detecting objects is important and more study is done on improve the detecting parameters. The proposed structures are developed from bulk to quantum well and quantum dots in recently years. In this work at reason insensitivity to incident light polarization, flexible operation wavelength, high operation temperature, inherent photovoltaic effect, low capture probability we study the structure of quantum dot infrared photodetectors and then for improve the detecting parameters structure of two layers quantum dot separated with a layer thin barrier (bilayer). And then a...
Investigation and Characterization of the Optical Response of High-Tc Josephson junction
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
Josephson junctions are the basic elements of superconducting technology. They play the same role of p-n junctions in semiconductor technology. Here, we investigated on the optical responses of the fabricated Josephson junctions in order to gain high sensitive optical sensors. The emission has both thermal and non-thermal effect on the current-voltage characteristics of the junctions. While the bolometric effect is the result of slight changes in the bias temperature of device, the non-thermal effect is due to depairing of Cooper pairs and generation of quasi-particles, which is dominant in temperatures far below TC especially in the case the superconducting layer is optically thin. In this...
Fabrication and Optical Response Characterization of High-Tc Superconductor Josephson Junction
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
Design of superconducting material based wide band radiation detectors has recently been attractive. Interesting features of detectors, which are based on Josephson Junctions such as high sensitivity in a wide range of frequencies and low power consumption, potentially have many advantages over other semiconductor-based photo-detectors. According to variety of applications of high-Tc superconductors, particularly YBCO, and significant progress in manufacturing of thin films and Josephson junctions, this thesis mainly focuses on investigation of radiation effects on I-V characteristics of high-Tc step-edge Josephson junctions experimentally. The current-voltage characteristics of fabricated...