Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Gamani Karunasiri, James Luscombe. Includes bibliographical references (p. 51-53). Also available online.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Gamani Karunasiri, James Luscombe. Includes bibliographical references (p. 67-69). Also available online.

Thesis (M.S. in Applied Physics)--Naval Postgraduate School, December 2004. / Thesis advisor(s): Gamani Karunasiri. Includes bibliographical references (p. 61-63). Also available online.

This thesis presents analysis and characterization of performance of a newly designed, multicolor quantum well infrared photodetector (QWIP). Specifically, it focuses on a detector capable of detecting infrared emissions in the near infrared (NIR), mid-wavelength infrared (MWIR), and long-wavelength infrared (LWIR). Through photocurrent spectroscopy and performance analysis, this prototype detector can be classified and prepared for possible future use within the U.S. Armed Forces. Certain military applications require a highly accurate, reliable, sensitive, and multispectral infrared detector to identify targets and ensure mission success. By designing and fabricating a multicolor quantum well infrared photodetector, simultaneous detection of targets in the near infrared, mid-wavelength infrared and long-wavelength infrared is possible using only one detector. In addition, power and cooling requirements for quantum well infrared detectors makes them suitable for use in the field. / US Navy (USN) author.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Gamani Karunasiri, James Luscombe. Includes bibliographical references (p. 45-46). Also available online.

Thesis (M.S. in Physics)--Naval Postgraduate School, September 2003. / Thesis advisor(s): Gamani Karunasiri, James Luscombe. Includes bibliographical references (p. 59-60). Also available online.

The major focus of the research project is to use infrared sensors associated with virtual sensors to measure the temperature of the heated plastic sheet in a thermoforming oven. In this work, we designed a sensor system to correctly and efficiently measure plastic sheet temperature and reduce the cost of instrumentation. The thesis consists of three parts. The first part is to optimally distribute IR sensors and virtual sensors in order to minimize the number of IR sensor and keep an acceptable accuracy on estimation of virtual sensors under the design constrain. Since IR sensor measurements may be inaccurate due to physical faults during the process, the second part is the sensor faults detection and isolation (FDI) to automatically detect and isolate the faulty sensors. In most situations the faulty sensors cannot be fixed immediately during process or production. Therefore, the last part is to use virtual sensors to replace the faulty IR sensors in order to keep production going. / The thesis project continues the work at the Industrial Automation Lab on sheet reheat phase in thermoforming. While the system model was changed into a larger scale, the modeling methodology and linearization assumption are the same as the previous work, which were verified. As a result, the system model and linearized model can be considered as valid. / As the whole project is only based on simulation, the measurement errors may become larger for the practical application.

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Near infrared (NIR) light detection has drawn substantial attentions in a variety of applications. NIR detectors prepared by the solution processable organic semiconductors and organic-inorganic hybrid material systems have the advantages for achieving flexible, light weight and large area NIR detection devices. The aim of this research work is to study the modulation of the photo-generated charge carriers in perovskite and polymer systems for attaining high performing solution-processable NIR phototransistors (PTs) and photodiodes (PDs). In the first part, an organo-lead halide perovskite/polymer bi-layer channel PT is discussed. Compared to the performance of the polymer only PTs, the PTs with a perovskite/polymer hybrid channel exhibit a profound broadband enhancement in photoresponsivity over the light wavelength range from UV to NIR. The improved performance in the hybrid perovskite/polymer PTs is closely associated with the efficient charge separation and transfer between the perovskite and polymer functional layers in the heterojunction. With the success in developing the bi-layer perovskite/polymer PTs, the enhancement in NIR detection is further realized in PTs by incorporating a bulk heterojunction (BHJ) channel. The BHJ channel is formed by blending NIR sensitive polymer donor with three different acceptor materials for enhancing exciton dissociation and charge separation efficiency. It is shown that the use of donor/acceptor BHJ greatly facilitates the dissociation of photo generated excitons. The efficient exciton dissociation helps to boost the utilization of the photo generated excitons, and thereby improves the photoresponsivity. Although the PTs with a BHJ channel possess high photoresponsivity, the photosensitivity of these NIR PTs is still less than satisfactory. The results reveal that a higher activation energy of charge carriers is favorable for a lower carrier density in the channel. While under NIR light illumination, the mobile charge carriers, created due to the dissociation of the photo generated excitons, result in a dramatic increase in carrier density in the active channel. The increase in carrier density under NIR illumination, gives rise to a higher channel current, thereby a higher photosensitivity. A pixel-less NIR imaging device based on light up-conversion from near-infrared to green is demonstrated. A polymer donor/non-fullerene acceptor BHJ serving as the NIR sensitive unit is integrated monolithically with a perovskite-based light emitting diode (LED) unit for achieving light up-conversion from NIR to visible light. The BHJ serves as an NIR sensitive hole injection layer in the perovskite LEDs. Therefore, the efficient electroluminescence in area where NIR-induced efficient charge injection occurs in the LEDs can be displayed clearly, producing the visible light image. The photoresponsivity of perovskite based UV-Visible-NIR photodiodes (PDs) is discussed in the last part of the thesis. A periodic nano-grating hole transporting layer (HTL), formed by the nano-imprinting, is adopted for enhancing the photoresponsivity of the PDs. Theoretical simulation reveals that the periodic nano-grating HTL helps to improve light absorption in the active layer, caused by the enhanced light in-coupling effect. In the meantime, the nano-grating HTL based PDs exhibit weak angular dependency as compared to that of the planar control ones which is appealing for wide angle light detections.