Thesis (Ph.D.)--University of Western Australia, 2005.

Thesis (Ph. D.)--University of North Texas, Dec., 2007. / Title from title page display. Includes bibliographical references.

Mercury cadmium telluride is important in the detection of electromagnetic radiation in the eight to twelve micron atmospheric window for infrared imaging systems. High resolution infrared imaging systems use either large (256x256 element to 1024x1024 element) staring arrays or much smaller (1-6 element) scanned arrays in which the image is optically scanned across the detectors. In scanned arrays, high resolution and sensitivity may result in the scan direction not being parallel to the detector bias current. The response of an infrared detector to uniform illumination is investigated. It is found that variations in the detector thickness result in significant changes in output voltage. Scanned detectors are modeled in five different orientations; scan parallel to bias, scan opposite to bias, scan perpendicular to bias, and two orientations of the scan diagonal to the bias. The response is analyzed for two cases: 1) the size of the scanned radiation equal to the size of the detector and 2) when the pixel width is half of the width of the detector, but of equal length. Results of the simulation show that the fastest response occurs when the scan and bias are parallel. The largest response occurs when the scan direction is diagonal to the bias, but the response time is much slower than when the bias is parallel to the scan. Therefore, a tradeoff must be made between maximum signal and speed of response. Test detectors are being fabricated and will be tested at FLIR Systems Inc., Portland, Oregon, to confirm the model predictions. / Graduation date: 1992

[Truncated abstract] Infrared radiation detectors find application in a wide range of military and civilian applications: for example, target identification, astronomy, atmospheric sensing and medical imaging. The greatest sensitivity, response speed, and wavelength range is offered by infrared detectors based on HgCdTe semiconductor material, the growth and characterisation of which is the subject of this thesis. Molecular Beam Epitaxy (MBE) is a versatile method of depositing layers of semiconductor material on a suitable crystalline substrate. In particular, MBE facilitates the growth of multilayer structures, thus allowing bandgap engineered devices to be realised. By modulating the bandgap within the device structure it is possible to improve the sensitivity or increase the operating temperature of photodetectors when compared to devices fabricated on single layer material. Furthermore, dual-band detectors may be fabricated using multi-layered HgCdTe material. The bulk of this thesis is concerned with the development of the MBE process for multilayer growth, from modelling of the growth process to characterisation of the material produced, and measurement of photoconductive devices fabricated on these wafers. In this thesis a previously published model of HgCdTe growth by MBE is reviewed in detail, and is applied to the growth of double layer heterostructures in order to determine the optimum method of changing the mole fraction between layers. The model has been used to predict the change in the temperature of the phase limit when the mole fraction and growth rate change suddenly as is the case during growth of an abrupt heterostructure. Two options for growth of an abrupt heterostructure were examined (a) modulating the CdTe flux and (b) modulating the Te flux. The change in the phase limit temperature between the layers was calculated as being 4:1±C for option (a) and 5:2±C for option (b) when growing a Hg(0:7)Cd(0:3)Te/Hg(0:56)Cd(0:44)Te heterostructure

Thesis (Ph.D.)--University of Western Australia, 2005.

Thesis (Ph.D)--University of Western Australia, 2007.

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains x, 72 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 69-72).

Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / M.S.

Thesis (Ph. D.)--University of Massachusetts Amherst, 2009. / Includes bibliographical references (p. 153-161). Print copy also available.

Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains ix, 72 p. : ill. Includes abstract. Includes bibliographical references (p. 68-72).