Publications

Reticular Metalation in Metal-Organic Frameworks for Nanocasting and Interface Construction

Xiang Gao
Roya Maboudian
2019
Metal-organic frameworks (MOFs) are a class of porous, crystalline materials constructed by extending the linkages between inorganic and organic molecular building blocks through strong bonds. Because of their high porosities, accessible interconnected pore structures, and designable backbones, MOFs have been used in applications ranging from as catalystsupports, membrane substrates, sensing layers, and casting templates...

MEMS-Actuated Carbon Fibers

Rachel Zoll
Kristofer S.J. Pister
2019

This thesis presents a MEMS actuator capable of extruding or pulling itself along a sub-10μm diameter carbon fiber. The compact silicon microfabricated MEMS actuator can extrude fibers over many millimeters of distance with micron-level precision and is powered externally via high-voltage control signals.

One specific application demonstrated in this work is the insertion of microelectrodes for cortical neural recording. Microwire and microelectrode arrays used for cortical neural...

Electronic Interfaces for Bacteria-Based Biosensing

Tom Zajdel
Michel M. Maharbiz
2018

Bacterial sensing systems have evolved to detect complex biomolecules, operating near fundamental physical limits for biosensing. No modern engineered biosensor has managed to match the efficiency of bacterial systems, which optimize for each sensing application under constraints on response time and sensitivity. An emerging approach to address this short fallis to build biosensors that electronically couple microbes and devices to combine the sensing capabilities of bacteria with the communication and data processing...

The Ionocraft: Flying Microrobots With No Moving Parts

Daniel Drew
Kristofer S.J. Pister
2018
Enabling a future full of insect-scale robots will require progress on a huge number of fronts, one of which is the development of mobility platforms designed to operate beyond the scaling frontier of commercially available solutions. The vast majority of researchers seeking to create functional centimeter-scale flying robots have turned towards biomimeticpropulsion mechanisms, specifically flapping wings. In this work I take a very different tack, investigating a propulsion mechanism with no natural analogue —...

Micromechanisms Using Sidewall Beams

Michael Judy
Roger T. Howe
Richard S. Muller
Albert P. Pisano
1994
A process technology is developed for surface micromachining that achieves sub-micrometer linewidths without the use of advanced lithography equipment. This technique is based upon the sidewall spacer technique that has been used extensively in integrated circuits. The sidewall spacer technique, stated simply, is to deposit a conformal film over a vertical step on the substrate. The conformal film is then anisotropically etched leaving a siclewall spacer or beam. Traditionally these sidewall "stringers" were a nuisance in surface micromachining great care had to be expended to remove...

Silicon Carbide Bipolar Junction Transistors for High Temperature Sensing Applications

Nuo Zhang
Albert P. Pisano
Tsu-Jae King Liu
Liwei Lin
2014

An integrated sensing module capable of operating at high temperatures would be beneficial to a number of industrial applications, such as automotive industries, aerospace systems, industrial turbines and deep-well drilling telemetric systems. Consider industrial turbines as an example. It is important to monitor a variety of physical parameters within the hot sections of the turbines in order to increase turbine efficiency, reliability and to reduce pollution. In addition, real-time monitoring can help to detect and predict the failures of critical components in a timely fashion to...

Dopant Profiling of III-V Nanostructures for Electronic Applications

Alexandra Ford
Yuri Suzuki
Junqiao Wu
Ali Javey
2011

High electron mobility III-V compound semiconductors such as indium arsenide (InAs) are promising candidates for future active channel materials of electron devices to further enhance device performance. In particular, compound semiconductors heterogeneously integrated on Si substrates have been studied, combining the high mobility of III-V semiconductors and the well-established, low cost processing of Si technology. However, one of the primary challenges of III-V device fabrication is controllable, post-growth dopant profiling. Here InAs nanowires and ultrathin layers (nanoribbons...

Device Physics and Material Properties of Two-Dimensional Semiconductors

Sujay Desai
Ali Javey
Junqiao Wu
Tsu-Jae King Liu
Jeffrey Bokor
2018

Device architecture and materials innovations have enabled transistor scaling for the last several decades, boosting the performance of electronics, increasing the speed of communication and computational systems, lowering power consumption and reducing costs per operation. Two-dimensional (2D) materials have gained tremendous attention in the last decade, after the discovery of graphene which has exceptional properties like high carrier mobility, ultra-thin van der Waals connected layers (~ 0.3 nm thick), high tensile strength, etc.

Transition metal...

Transparent Micro-electrocorticography (μECoG) Arrays for Optogenetic Mapping of Surface Potentials

Brian Pepin
Michel M. Maharbiz
2013

Electrocorticography (ECoG) has been used for decades clinically to help localize epileptic seizures but has only recently come into vogue as a potentially useful imaging modality. This change has partially been driven by the development of new micro-electrocorticography (µECoG) arrays which take advantage of modern surface micromachining techniques to achieve extremely dense electrode arrays packed with tiny (less than500µm diameter) electrodes. As an imaging tool, µECoG may be improved by taking advantage of the transparent µECoG array technology developed at the University of...

Parametric Oscillation with Wineglass Disk Resonators

Thanh-Phong Nguyen
Clark T.-C. Nguyen
Bernhard E. Boser
2018

Parametric oscillation provides another avenue to excite micro electro-mechanical resonators into oscillation. Rather than driving the resonator at its resonant frequency, modulating the stiffness of the resonator forces this motion. While this technique can lead to failures, it also can provide methods for frequency division, phase noise reduction, and sustaining oscillations of various frequency with a single amplifier. This work models the voltage conditions for parametric oscillation and compares them to measured results with an accuracy of 15%. Discrepancies caused by...