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Solid State Ph Sensor Based On Light Emitting Diodes (Led) As Detector Platform, King Tong Lau, Roderick Shepherd, Danny Diamond, Dermot Diamond Jan 2006

Solid State Ph Sensor Based On Light Emitting Diodes (Led) As Detector Platform, King Tong Lau, Roderick Shepherd, Danny Diamond, Dermot Diamond

Australian Institute for Innovative Materials - Papers

A low-power, high sensitivity, very low-cost light emitting diode (LED)-based device developed for low-cost sensor networks was modified with bromocresol green membrane to work as a solid-state pH sensor. In this approach, a reverse-biased LED functioning as a photodiode is coupled with a second LED configured in conventional emission mode. A simple timer circuit measures how long (in microsecond) it takes for the photocurrent generated on the detector LED to discharge its capacitance from logic 1 (+5 V) to logic 0 (+1.7 V). The entire instrument provides an inherently digital output of light intensity measurements for a few cents. A …


Antenna-Coupled Infrared And Millimeter-Wave Detectors: Fabrication, Measurement And Optimization, Charles Middleton Jan 2006

Antenna-Coupled Infrared And Millimeter-Wave Detectors: Fabrication, Measurement And Optimization, Charles Middleton

Electronic Theses and Dissertations

Antenna-coupled detectors provide uncooled, cost-effective solutions for infrared and millimeter-wave imaging. This work describes the design, fabrication, measurement, and optimization of several types of antenna-coupled detectors for LWIR (8 - 12 µm) and 94 GHz radiation. Two types of millimeter-wave antenna-coupled detectors were fabricated and tested: a slot antenna coupled to a bolometer, and a patch antenna coupled to a SiC Schottky diode. Electromagnetic modeling of the antennas helped guide the design of antennas with better impedance matching to the detectors. Schottky diodes are discussed as detectors for millimeter-wave and infrared radiation, with the goal of increasing the cutoff frequency …


Quantum Dot Infrared Photodetector Fabricated By Pulsed Laser Deposition Technique, Mohammed Hegazy, Tamer Refaat, Nurul Abedin, Hani Elsayed-Ali Jan 2006

Quantum Dot Infrared Photodetector Fabricated By Pulsed Laser Deposition Technique, Mohammed Hegazy, Tamer Refaat, Nurul Abedin, Hani Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Pulsed laser deposition is used to fabricate multilayered Ge quantum-dot photodetector on Si(100). Growth was studied by reflection high-energy electron diffraction and atomic force microscopy. The difference in the current values in dark and illumination conditions was used to measure the device sensitivity to radiation. Spectral responsivity measurements reveal a peak around 2 μm, with responsity that increases three orders of magnitude as bias increases from 0.5 to 3.5 V.