An Optofluidic Lens Biochip and an x-ray Readable Blood Pressure Microsensor: Versatile Tools for in vitro and in vivo Diagnostics.

Three different microfabricated devices were presented for use in vivo and in vitro diagnostic biomedical applications: an optofluidic-lens biochip, a hand held digital imaging system and an x-ray readable blood pressure sensor for monitoring restenosis. An optofluidic biochip–termed the ‘Microfluidic-based Oil-Immersion Lens’ (mOIL) biochip were designed, fabricated and test for high-resolution imaging of various biological samples. The biochip consists of an array of high refractive index (n = 1.77) sapphire ball lenses sitting on top of an oil-filled microfluidic network of microchambers. The combination of the high optical quality lenses with the immersion oil results in a numerical aperture (NA) of 1.2 which is comparable to the high NA of oil immersion microscope objectives. The biochip can be used as an add-on-module to a stereoscope to improve the resolution from 10 microns down to 0.7 microns. It also has a scalable field of view (FOV) as the total FOV increases linearly with the number of lenses in the biochip (each lens has ~200 microns FOV). By combining the mOIL biochip with a CMOS sensor, a LED light source in 3D printed housing, a compact (40 grams, 4cmx4cmx4cm) high resolution (~0.4 microns) hand held imaging system was developed. The applicability of this system was demonstrated by counting red and white blood cells and imaging fluorescently labelled cells. In blood smear samples, blood cells, sickle cells, and malaria-infected cells were easily identified. To monitor restenosis, an x-ray readable implantable blood pressure sensor was developed. The sensor is based on the use of an x-ray absorbing liquid contained in a microchamber. The microchamber has a flexible membrane that is exposed to blood pressure. When the membrane deflects, the liquid moves into the microfluidic-gauge. The length of the microfluidic-gauge can be measured and consequently the applied pressure exerted on the diaphragm can be calculated. The prototype sensor has dimensions of 1x0.6x10mm and adequate resolution (19mmHg) to detect restenosis in coronary artery stents from a standard chest x-ray. Further improvements of our prototype will open up the possibility of measuring pressure drop in a coronary artery stent in a non-invasively manner.PhDMacromolecular Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111384/1/toning_1.pd

Hydrogen Research for Spaceport and Space-Based Applications: Hydrogen Sensors and Systems

The activities presented are a broad based approach to advancing key hydrogen related technologies in areas such as fuel cells, hydrogen production, and distributed sensors for hydrogen-leak detection, laser instrumentation for hydrogen-leak detection, and cryogenic transport and storage. Presented are the results from research projects, education and outreach activities, system and trade studies. The work will aid in advancing the state-of-the-art for several critical technologies related to the implementation of a hydrogen infrastructure. Activities conducted are relevant to a number of propulsion and power systems for terrestrial, aeronautics and aerospace applications. Sensor systems research was focused on hydrogen leak detection and smart sensors with adaptive feedback control for fuel cells. The goal was to integrate multifunction smart sensors, low-power high-efficiency wireless circuits, energy harvesting devices, and power management circuits in one module. Activities were focused on testing and demonstrating sensors in a realistic environment while also bringing them closer to production and commercial viability for eventual use in the actual operating environment

Reconfigurable Receiver Front-Ends for Advanced Telecommunication Technologies

The exponential growth of converging technologies, including augmented reality, autonomous vehicles, machine-to-machine and machine-to-human interactions, biomedical and environmental sensory systems, and artificial intelligence, is driving the need for robust infrastructural systems capable of handling vast data volumes between end users and service providers. This demand has prompted a significant evolution in wireless communication, with 5G and subsequent generations requiring exponentially improved spectral and energy efficiency compared to their predecessors. Achieving this entails intricate strategies such as advanced digital modulations, broader channel bandwidths, complex spectrum sharing, and carrier aggregation scenarios. A particularly challenging aspect arises in the form of non-contiguous aggregation of up to six carrier components across the frequency range 1 (FR1). This necessitates receiver front-ends to effectively reject out-of-band (OOB) interferences while maintaining high-performance in-band (IB) operation. Reconfigurability becomes pivotal in such dynamic environments, where frequency resource allocation, signal strength, and interference levels continuously change. Software-defined radios (SDRs) and cognitive radios (CRs) emerge as solutions, with direct RF-sampling receivers offering a suitable architecture in which the frequency translation is entirely performed in digital domain to avoid analog mixing issues. Moreover, direct RF- sampling receivers facilitate spectrum observation, which is crucial to identify free zones, and detect interferences. Acoustic and distributed filters offer impressive dynamic range and sharp roll off characteristics, but their bulkiness and lack of electronic adjustment capabilities limit their practicality. Active filters, on the other hand, present opportunities for integration in advanced CMOS technology, addressing size constraints and providing versatile programmability. However, concerns about power consumption, noise generation, and linearity in active filters require careful consideration.This thesis primarily focuses on the design and implementation of a low-voltage, low-power RFFE tailored for direct sampling receivers in 5G FR1 applications. The RFFE consists of a balun low-noise amplifier (LNA), a Q-enhanced filter, and a programmable gain amplifier (PGA). The balun-LNA employs noise cancellation, current reuse, and gm boosting for wideband gain and input impedance matching. Leveraging FD-SOI technology allows for programmable gain and linearity via body biasing. The LNA's operational state ranges between high-performance and high-tolerance modes, which are apt for sensitivityand blocking tests, respectively. The Q-enhanced filter adopts noise-cancelling, current-reuse, and programmable Gm-cells to realize a fourth-order response using two resonators. The fourth-order filter response is achieved by subtracting the individual response of these resonators. Compared to cascaded and magnetically coupled fourth-order filters, this technique maintains the large dynamic range of second-order resonators. Fabricated in 22-nm FD-SOI technology, the RFFE achieves 1%-40% fractional bandwidth (FBW) adjustability from 1.7 GHz to 6.4 GHz, 4.6 dB noise figure (NF) and an OOB third-order intermodulation intercept point (IIP3) of 22 dBm. Furthermore, concerning the implementation uncertainties and potential variations of temperature and supply voltage, design margins have been considered and a hybrid calibration scheme is introduced. A combination of on-chip and off-chip calibration based on noise response is employed to effectively adjust the quality factors, Gm-cells, and resonance frequencies, ensuring desired bandpass response. To optimize and accelerate the calibration process, a reinforcement learning (RL) agent is used.Anticipating future trends, the concept of the Q-enhanced filter extends to a multiple-mode filter for 6G upper mid-band applications. Covering the frequency range from 8 to 20 GHz, this RFFE can be configured as a fourth-order dual-band filter, two bandpass filters (BPFs) with an OOB notch, or a BPF with an IB notch. In cognitive radios, the filter’s transmission zeros can be positioned with respect to the carrier frequencies of interfering signals to yield over 50 dB blocker rejection

산화물/질화물 복합구조를 이용한 유연한 전자 및 광전소자 응용

학위논문 (박사) -- 서울대학교 대학원 : 자연과학대학 물리학과, 2020. 8. 이규철.물리적으로 강하고 유연한 그래핀과 같은 2차원 소재위에 성장된 무기물 나노소재로 구성된 복합차원 나노소재는 유연한 대면적 전자 및 광전소자로의 응용에 적합한 형태의 소재 구조이며, 실제로 이를 기반으로 한 유연한 수직형 전계효과 트랜지스터 및 발광다이오드 등을 포함한 많은 소자들이 개발되고 있다. 하지만, 처리된 정보를 저장하고 이를 사용자에게 전달하는 기능을 수행하기 위해선 보다 다양한 소자들이 개발되어야 할 필요가 있다. 본 학위논문은 이러한 수요를 충족시키기 위해, 복합차원 나노소재 기반 유연한 대면적 차세대 비휘발성 메모리 및 유연한 대면적 다파장 발광 다이오드의 개발에 대하여 다루고 있다. 복합차원 나노소재를 기반으로 차세대 비휘발성 메모리를 구현하기 위해 니켈 산화물 및 질화갈륨 이종구조로 구성된 마이크로디스크 형태의 소재를 그래핀 위에 성장하고, 본 소재의 상부 및 하부에 전극을 증착하여 전극/산화물/전극으로 구성된 형태의 산화물 기반 저항변화 메모리를 제조할 수 있었다. 마이크로디스크 형태의 소재의 사이가 떨어져있기 때문에 본 소자를 유연한 형태에서 구현하거나 1,000 회 이상의 구부림 뒤 소자의 특성을 파악할 때 소자 특성의 큰 변화 없이 정보가 안정적으로 저장되는 특성을 확인할 수 있었다. 뿐만 아니라, 니켈 산화물 기반 저항변화메모리를 동작할 때, 산화물 내부에 전도성이 높은 니켈 산화물이 필라멘트 형태로 구성되는데, 이를 발광다이오드의 나노전극으로 사용하여 저항변화메모리 내부의 필라멘트 역학에 대해서도 연구할 수 있었다. 한편, 저장된 정보를 사용자에게 정확하게 전달하기 위해선 발광다이오드의 한 픽셀 (pixel) 의 크기가 수 마이크로미터 이하로 작아야하고, 빨강, 초록, 파랑색의 빛을 발광할 수 있어야 하는데 이는 현재 이용되고 있는 픽 앤 플레이스 (pick and place) 기술을 이용하여 제조할 때 소자 제조의 효율성 및 재현성에 한계를 보이고 있다. 본 학위논문에서는 이를 극복하기 위한 방법의 하나로, 다양한 색을 발광할 수 있는 발광다이오드를 하나의 그래핀 기판위에 동시에 성장하는 방법을 제시하고 이를 유연한 다파장 발광다이오드로 구현하는 방법에 대해 기술하고 있다. 본 소자를 구현하기 위해 다양한 모양의 질화갈륨 및 산화아연 이종구조를 그래핀 위에 성장하는 방법을 개발하였는데, 산화아연 나노튜브의 간격을 다르게 설정하여 성장하고 이 위에 질화갈륨을 성장하면 질화갈륨의 성장률이 나노튜브의 간격에 따라 다르게 형성되어 다른 모양의 마이크로 발광다이오드가 성장되는 것을 이용하였다. 각기 다른 발광다이오드에 같은 전압을 가해줬을 때 성장률의 차이로 인한 다중 양자 우물 조성의 변화 및 소재 내부의 결함으로 인해 각기 다른 파장의 색이 발광되는 특성을 확인하였고, 유연한 형태에서도 안정적으로 발광특성이 유지되는 것을 확인할 수 있었다.The hybrid dimensional nanostructrures composed of high-quality inorganic nanostructures grown directly on two-dimensional (2D) materials such as graphene offers a novel material system for flexible electronics and optoelectronics. Indeed, the hybrid dimensional nanostructures have been fabricated to flexible electronics/optoelectronics and attracted many attentions with their excellent performances. Despite of the demonstration of flexible devices using the hybrid dimensional nanostructures, there remains a lot of devices that need to be further investigated in order to realize future electronics/optoelectronics such as wearable devices. This thesis presents the hybrid material system composed of oxide/nitrid heterostructures grown on graphene films and their applications on flexible non-volatile memory and flexible multi-color LEDs.Abstract Chapter 1. General Introduction 1 1.1. Motivation: Potentials of hybrid dimensional nanomaterials for flexible electronic/optoelectronic device applications 1 1.2. Thesis objective and approach 3 1.3. Thesis outline 4 Chapter 2. Literature survey 6 2.1. Oxide-based flexible electronics 6 2.1.1. Current status of oxide-based electronics 8 2.1.2. Next generation oxide-based electronics: ReRAM 12 2.1.3. Flexible ReRAM 17 2.1.3.1. ReRAM on plastic substrates 17 2.1.3.2. Transfer of ReRAM layers on flexible substrates 20 2.2. Nitride-based flexible optoelectronics 23 2.2.1. Current status of nitride-based optoelectronics 23 2.2.2. Next generation nitride-based optoelectronics: flexible & high-resolution LED 29 2.3. Hybrid dimensional material systems for flexible electronics and Optoelectronics 34 2.3.1. Growth of oxide & nitride nano-/micro-structures on graphene layers35 2.3.2. Functional devices using hybrid dimensional material Systems 45 2.3.2.1. Electronics 47 2.3.2.2. Optoelectronics 50 Chapter 3. Experimental Techniques 53 3.1. Growth techniques 53 3.1.1. Metalorganic vapor-phase epitaxy system 53 3.1.1.1. Gas delivery system 53 3.1.1.2. Reactor and temperature controller 55 3.1.1.3. Exhaust disposal system and low pressure pumping System 56 3.2. Structural characterization 57 3.2.1. Morphology inspection 57 3.2.2. Crystallographic and microstructural investigations 57 3.2.2.1. Transmission electron microscopy 57 3.3. Optical characterization 58 3.3.1. Photoluminescence & electroluminescence spectroscopy 58 3.4. Electrical characterization 59 3.4.1. Current-Voltage measurement 59 Chapter 4. Flexible ReRAM based on hybrid dimensional material systems 60 4.1. Introduction 60 4 .2. Growth of oxide/nitride hybrid structures on graphene layers 61 4.2.1. ZnO nanowall growth CVD-graphene films 62 4.2.2. Growth of GaN microdisk arrays 62 4.2.3. Growth of resistive switching layers 65 4.4. Fabrication of flexible ReRAM 65 4.5. Resistive switching characteristics 69 4.6. Discussion for the mechanism of resistive switchings using oxide/nitride hybrid structures 78 4.6.1. Fabrication of ReRAM/LED hybrid device 80 4.6.2. Real-time imaging of resistive switching dynamics 85 4.7. Summary 99 Chapter 5. Monolithic integration of morphology controlled GaN microstructures on graphene films for flexible & multi-color LEDs 101 5.1. Introduction 101 5.2. Morphology control of GaN microstructures on graphene films 103 5.2.1. Growth parameter: spacing & time 103 5.2.2. Growth behavior analysis 109 5.3. Fabrication of LEDs on graphene films 115 5.4. EL and electrical characteristics 118 5.5. High temperature operations of flexible LEDs 125 5.6. Summary 134 Chapter 6. Conclusion and Outlook 136 6.1. Conclusion 136 6.2. Future works and outlook 141 References 143 Abstract (Korean) 151Docto

NASA Tech Briefs, July 2007

Topics covered include: Miniature Intelligent Sensor Module; "Smart" Sensor Module; Portable Apparatus for Electrochemical Sensing of Ethylene; Increasing Linear Dynamic Range of a CMOS Image Sensor; Flight Qualified Micro Sun Sensor; Norbornene-Based Polymer Electrolytes for Lithium Cells; Making Single-Source Precursors of Ternary Semiconductors; Water-Free Proton-Conducting Membranes for Fuel Cells; Mo/Ti Diffusion Bonding for Making Thermoelectric Devices; Photodetectors on Coronagraph Mask for Pointing Control; High-Energy-Density, Low-Temperature Li/CFx Primary Cells; G4-FETs as Universal and Programmable Logic Gates; Fabrication of Buried Nanochannels From Nanowire Patterns; Diamond Smoothing Tools; Infrared Imaging System for Studying Brain Function; Rarefying Spectra of Whispering-Gallery-Mode Resonators; Large-Area Permanent-Magnet ECR Plasma Source; Slot-Antenna/Permanent-Magnet Device for Generating Plasma; Fiber-Optic Strain Gauge With High Resolution And Update Rate; Broadband Achromatic Telecentric Lens; Temperature-Corrected Model of Turbulence in Hot Jet Flows; Enhanced Elliptic Grid Generation; Automated Knowledge Discovery From Simulators; Electro-Optical Modulator Bias Control Using Bipolar Pulses; Generative Representations for Automated Design of Robots; Mars-Approach Navigation Using In Situ Orbiters; Efficient Optimization of Low-Thrust Spacecraft Trajectories; Cylindrical Asymmetrical Capacitors for Use in Outer Space; Protecting Against Faults in JPL Spacecraft; Algorithm Optimally Allocates Actuation of a Spacecraft; and Radar Interferometer for Topographic Mapping of Glaciers and Ice Sheets

Point of Care Diagnostics and Health Monitoring Devices

Existing disease screening methods mostly rely on symptom based diagnosis. This is mainly because of lack of accessibility and cost associated with the tests. Testing for the presence of the disease after the onset of symptoms has a negative impact on chances of survival and treatment costs. Miniaturized low cost diagnostic devices that can be used outside the hospital setting can provide continuous health monitoring and aid in early diagnosis. This thesis presents techniques to develop such disease screening and health monitoring devices. The techniques presented here focus on medical devices that can benefit from microfluidic devices, fluorescence imaging, and antibody testing

MEMS Accelerometers

Micro-electro-mechanical system (MEMS) devices are widely used for inertia, pressure, and ultrasound sensing applications. Research on integrated MEMS technology has undergone extensive development driven by the requirements of a compact footprint, low cost, and increased functionality. Accelerometers are among the most widely used sensors implemented in MEMS technology. MEMS accelerometers are showing a growing presence in almost all industries ranging from automotive to medical. A traditional MEMS accelerometer employs a proof mass suspended to springs, which displaces in response to an external acceleration. A single proof mass can be used for one- or multi-axis sensing. A variety of transduction mechanisms have been used to detect the displacement. They include capacitive, piezoelectric, thermal, tunneling, and optical mechanisms. Capacitive accelerometers are widely used due to their DC measurement interface, thermal stability, reliability, and low cost. However, they are sensitive to electromagnetic field interferences and have poor performance for high-end applications (e.g., precise attitude control for the satellite). Over the past three decades, steady progress has been made in the area of optical accelerometers for high-performance and high-sensitivity applications but several challenges are still to be tackled by researchers and engineers to fully realize opto-mechanical accelerometers, such as chip-scale integration, scaling, low bandwidth, etc

Laboratory for Atmospheres Instrument Systems Report

Studies of the atmospheres of our solar system's planets including our own require a comprehensive set of observations, relying on instruments on spacecraft, aircraft, balloons, and on the surface. These instrument systems perform one or both of the following: 1) provide information leading to a basic understanding of the relationship between atmospheric systems and processes, and 2) serve as calibration references for satellite instrument validation. Laboratory personnel define requirements, conceive concepts, and develop instrument systems for spaceflight missions, and for balloon, aircraft, and ground-based observations. Balloon and airborne platforms facilitate regional measurements of precipitation, cloud systems, and ozone from high-altitude vantage points, but still within the atmosphere. Such platforms serve as stepping-stones in the development of space instruments. Satellites provide nearly global coverage of the Earth with spatial resolutions and repetition rates that vary from system to system. The products of atmospheric remote sensing are invaluable for research associated with water vapor, ozone, trace gases, aerosol particles, clouds, precipitation, and the radiative and dynamic processes that affect the climate of the Earth. These parameters also provide the basic information needed to develop models of global atmospheric processes and weather and climate prediction. Laboratory scientists also participate in the design of data processing algorithms, calibration techniques, and the data processing systems