| Micromechanical structures perform nanoscale motion by responding to physically and chemically induced external stimuli. This dissertation describes the development of novel bimorph opto-mechanical sensor array to increase sensitivity without sacrificing a fundamental noise limit, or thermal vibration noise. Additionally, for screening of selective sensor coating material, a high throughput nano-chemo-mechanical sensor array platform is presented.;A Flip-Over Bi-material (FOB) beam has been designed to increase the sensitivity of micromechanical structures. The FOB beam has a typical configuration such that a material layer coats the top and bottom of the second material at different regions along the beam length. By multiple interconnections of FOB beams, the deflection or sensitivity can be amplified, and the piston motion of a sensing structure can be achieved. The FOB beam has 53% higher thermo-mechanical sensitivity than a conventional one. Using the FOB beam design, a micro-opto-mechanical sensor has been developed to have a symmetric structure such that beam deflection is converted into a linear displacement of a reflecting surface, which is used for optical interferometry. The designed sensor has been fabricated by surface micromachining techniques using a transparent quartz substrate for optical measurement. Within a sensor area of 100 μm × 100 μm, the thermo-mechanical sensitivity ST = 180 nm/K has been experimentally obtained.;Two bimorph structures performing piston motion are described from the optimal design point of view. For both the structures, mathematical modelling has been performed and optimal geometric parameters for maximum sensitivity have been derived. For molecular sensing applications, the established mathematical modelling agrees well with the FEM simulation results. In the same device footprint, the FOB sensor design having interconnected FOB structures has higher signal to noise ratio than a simple bimorph cantilever sensor design.;For high throughput target specific coating material search, a 2-D multiplexed cantilever sensor array platform has been developed. Using this 2-D sensor array platform, chemical sensing experiments have been performed for water, ethanol, and toluene vapor. Thermal and chemical vapor responses of 18 cantilevers, which are coated with three alkane thiols having different functional end groups, have been measured simultaneously. From these experiments, chemically induced nanoscale motion of cantilevers for various humidity or vapor concentration levels, and response differentiation with different functional end groups of thiols have been observed. |
