Thesis (Ph.D.) -- University of Texas at Arlington, 2008.

This thesis presents the development and characterisation of an ultra-sensitive, silicon nanowire (SiNW)-based biosensor devices for the detection of disease biomarkers.

University of Macau / Faculty of Science and Technology. / Department of Electromechanical Engineering

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 6, 2007) Includes bibliographical references.

Thesis (Ph. D.)--Lehigh University, 2006. / Includes vita. Includes bibliographical references (leaves 173-191).

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: vacuum; shape and deformation measurement; MEMS; vibrometry; scanning white light; Interferometry; thermal; vibration. Includes bibliographical references (136-139 leaves ).

The high-performance accelerometers with micro-gravity resolution and large dynamic range at very low frequencies are not only used in GPS-augmented inertial navigation, monitoring of aircrafts and space station, but also used in monitoring wind turbines for green energy. This dissertation presents the design and development of a mixed-signal, low-noise, and fourth-order sigma-delta interface circuit for the MEMS capacitive micro-gravity accelerometer. A fully-differential switched-capacitor (SC) amplifier architecture is developed with the low-frequency noise reduction through the integration of chopper-stabilization technique with lateral BJT at input stage. The effectiveness of different noise reduction techniques is also compared and verified. The application of fourth-order SC sigma-delta modulation concept to the inertial-grade accelerometer is to achieve the benefits of the digitization of the accelerometer output without compromising the resolution of the analog front-end. This open-loop interface provides 1-bit digital output stream and has the versatility of interfacing sensors with different sensitivities while maintaining minimum power dissipation and maximum dynamic range. The micromechanical accelerometers are fabricated in thick silicon-on-insulator (SOI) substrates. The accelerometer operates in air and is designed for non-peaking response with a bandwidth of 500 Hz.

Highly sensitive optical displacement detection methods implemented in a small volume and with reduced power consumption have a potential to compete with commonly used capacitance based methods in micromechanical sensor systems. This dissertation presents the design, implementation, and characterization of a miniaturized optomechanical displacement sensor system heterogeneously integrated with a coherent laser source and optoelectronic readout as a step in realizing this potential. The sensor uses a phase-sensitive diffraction grating built on a transparent substrate to achieve interferometric sensitivity in a small volume. The device sensitivity is actively optimized via the built-in electrostatic actuation capability, which may be utilized for self calibration and force feedback operation. Optical interconnect through the backside of the sensor enables compact integration with optoelectronic components. For optical readout, a custom-designed silicon photodiode array has been fabricated including deep reactive ion etching of through-wafer holes. The hybrid-integrated system has been implemented and characterized in an acoustic sensor application using both continuous wave and pulsed lasers to show reduced power consumption potential. Comprehensive diffraction analysis has been carried out for optical design of the integrated sensor. Furthermore, a fully-vectorial method has been formulated for general multilayered grating structures and compared with the scalar diffraction approach to investigate the effects of polarization and grating periods. In addition, a grating-assisted resonant-cavity-enhanced (GARCE) detection method has been proposed to improve the displacement sensitivity in optomechanical microsensors. Fabrication of the GARCE structures based on both metallic and dielectric mirrors has been successfully demonstrated, and preliminary experimental results have shown a good agreement with theoretical predictions. The concepts developed and demonstrated in this thesis form a technology platform which already had an impact in a variety of applications including optical microphones, micromachined ultrasonic transducers and transducers arrays, micromachined inertial sensors, and scanning probe microscopy.

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xiv, 180 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 177-180).

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Oscar Biblarz, Jose Sinibaldi. Includes bibliographical references (p. 67-69). Also available online.