Physical Sensors & Devices

Research that includes:

  • Silicon MEMS actuators: comb, electro-thermal, and plastic deformation
  • Precision electronic sensing and measurements of capacitive, frequency, and coulombic MEMS variables
  • Structures and architectures for gyroscopes, accelerometers, micro strain gauges for direct application to rigid structures e.g., steel, and levitated MEMS

NT25: VLSI MEMS Switch

Qingquan Liu
2006

Two important advantages of MEMS switches are their ability to survive heat and radiation. In addition, there has been increasing demand for passing transistor replacement in specific reconfigurable computing and signal routing application; passing transistors used in VLSI exhibit on-state resistances of thousands of ohms or more, which causes signal delay and increased power consumption. In this project, the design, fabrication and characterization of MEMS contact switches customized for VLSI are presented, herein referred to as “VLSI MEMS switches”.

Project end...

NT23: Ni Electroplated Vertical Comb-Drive Actuator

Zhihong Li
2004

A low-cost, vertical comb-drive actuator has been developed employing a thick photoresist and electroplating process. The vertical comb-drive actuator (VCA) will be employed for optical applications such as scanning mirrors and optical communication as well as other devices such as tunable capacitors

Project end date: 08/18/04

BPN959: Self-Righting for Micro Robots

Alexander Alvara
2022

In developing micro-robots for exploration in non-uniform terrain, it is often the case that robots fall over. This work seeks to provide a solution in the self-righting of autonomous micro-robots to overturn a 1cc, 1 gram cube microrobot with regular octahedral symmetry that has fallen on either of its four sides and overturning said microrobot once upside down. Our design currently consists of a 3-bar linkage in conjunction with an electrostatic inchworm motor. First-generation devices are in fab as of August. Hand analysis indicates that self-righting from any face should be...

BPN857: Miniature Autonomous Rockets

Alexander Alvara
2022

Pico air vehicles (PAVs), sub-5cm aerial vehicles, are becoming more feasible due to advances in wireless mesh networks, millimeter-scale propulsion, battery technology, and MEMS control surfaces. Our goal is to develop an aerodynamic MEMS control surface that could be used in PAV applications. This device will use electrostatic inchworm motors (capable of outputting 15mN) to extend an airfoil through 10 degrees. Using information from previous work that demonstrated roll control, we expect to extend automated flight control to pitch and yaw. We predict and output torque of 2.3 uNm,...

BPN930: Robust MEMS Inchworm Motors

Daniel Teal
Dillon Acker-James
Alex Moreno
Alexander Alvara
2022

We are developing robust, high force, low power, and efficient MEMS inchworm motors for microrobots. So far, we have created 3x4.7mm motors in a 40um SOI process capable of linearly actuating a shuttle with 15mN force and 5mm/s travel at < 1mW power draw to > 50mm displacement. By integrating these motors into 550um thick reinforcing silicon substrate structures we created a microgripper capable of reliably lifting 1g weights and other macroscopic objects. We also showed gripper operation off solar power in BSAC project BPN873. Finally, we have analyzed motor efficiency, an...

BPN958: Printed Miniaturized Li-Ion Batteries for Autonomous Microsystems

Anju Toor
2022

Despite the popularity and widespread demand for miniaturized electronic devices, limited advances have been made to design energy storage mechanisms that can satisfy their power and size requirements. We have developed a fabrication process to produce miniature Li-ion batteries by combining the stencil printing process to deposit thick high capacity electrodes and an adhesive based sealing method for battery packaging, with active areas as small as 1 mm2. The battery consists of printed anode and cathode layers based on graphite and lithium cobalt oxide (LCO) respectively. These...

BPN877: Pulse Acquisition and Diagnosis for Health Monitoring

Ruiqi Guo
2022

Traditional Chinese medicine(TCM) has existed for more than two thousand years and one of the important diagnostic methods is the pulse diagnosis. It generally takes decades of training for a practitioner to master this skill as pulse acquisition and diagnosis require long-term experiences and are very subjective. The project aims to use the combination of advanced sensor technology and artificial intelligence to emulate the TCM practice for health monitoring. A flexible piezoelectric film is designed to record the wrist pulse data. A group of representative pulse features has been...

Synthesis and Gas Sensing Properties of NiO/ZnO Heterostructured Nanowires

Sikai Zhao
Yanbai Shen
Yong Xia
Aifei Pan
Zhou Li
Carlo Carraro
Roya Maboudian
2021

In this study, we report on the synthesis of the NiO/ZnO heterostructured nanowires by a facile two-step liquid phase route and their gas sensing characteristics employing Au interdigitated electrodes integrated on a miniature ceramic heater. Microstructural characterizations indicate that flocculent NiO particles are uniformly assembled on the outer surfaces of the single-crystalline ZnO nanowires, with diameters around 50 nm and lengths ranging from 500 nm to several μm. The gas sensing investigation indicates that the sensors based on NiO/ZnO heterostructured nanowires exhibit high...

In-Situ Synthesized N-Doped ZnO for Enhanced CO2 Sensing: Experiments and DFT Calculations

Yong Xia
Aifei Pan
Ya-Qiong Su
Sikai Zhao
Zhou Li
Adrian K. Davey
Libo Zhao
Carlo Carraro
Roya Maboudian
2022

Chemiresistive CO2 sensing is attractive due to low cost and ease of chip-level integration. Our previous studies (Yong Xia, 2021) showed the well-developed ZnO material fabricated by in-situ annealing exhibited good CO2 sensing performance. Here, we have expanded on those studies, including CO2 cyclic tests under both dry air and N2 background whereby a much higher response to CO2 in N2 background was observed. Detailed density functional theory calculations were conducted to understand the behavior. The results indicated nitrogen doping is mainly responsible for the observed response. In...

A New Chemresistive NO2 Sensing Material: Hafnium Diboride

Sikai Zhao
Yong Xia
Steven DelaCruz
Aifei Pan
Zhou Li
Yanbai Shen
Marcus A. Worsley
Carlo Carraro
Roya Maboudian
2022

While metal oxides and metal sulfides have been extensively studied for gas sensing applications, there are no extensive reports on gas sensing properties of metal diborides. Here, for the first time, we have investigated the conductometric gas sensing behavior of HfB2 nanoparticles. The HfB2 nanoparticles is synthesized via a sol-gel method and characterized using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The gas sensor is fabricated by drop casting the HfB2 nanoparticles on interdigitated Ag/Pd...