Hysteresis is treated as a history dependent branching, and the use of the classical Preisach model for the analysis of macroeconomic hysteresis is first discussed. Then, a new Preisachtype model is introduced as a macroeconomic aggregation of more realistic microeconomic hysteresis than in the case of the classical Preisach model. It is demonstrated that this model is endowed with a more general mechanism of branching and may account for the continuous evolution of the economy and its effect on hysteresis. Furthermore, it is shown that the sluggishness of economic recovery is an intrinsic manifestation of hysteresis branching.

Ion channel proteins have many conformational (metastable) states and, for this reason, they exhibit hysteresis. This fact is responsible for the non-Markovian stochastic nature of single ion channel recordings. It is suggested in the paper that the stochastic single channel recordings can be modeled as the random outputs of rectangular hysteresis loops driven by stochastic processes. The latter problem can be mathematically treated as an exit problem for stochastic processes or by using the theory of stochastic processes on graphs. It is also demonstrated in the paper that the collective action of sodium and potassium channels responsible for the generation and propagation of action potentials exhibit hysteresis. This demonstration is accomplished by using the inverse problem approach to the nonlinear Hodgkin-Huxley diffusion equation.

The Preisach model of hysteresis admits simple device realizations. It is suggested in the paper that these realizations can be utilized as unique data storage devices as well as analog global optimizers.

In this study, electronic properties of field-effect transistors (FETs) fabricated from exfoliated MoTe2 single crystals are investigated as a function of channel thickness. The conductivity type in FETs gradually changes from n-type for thick MoTe2 layers (above ≈ 65 nm) to ambipolar behavior for intermediate MoTe2 thickness (between ≈ 60 and 15 nm) to ptype for thin layers (below ≈ 10 nm). The n-type behavior in quasi-bulk MoTe2 is attributed to doping with chlorine atoms from the TeCl4 transport agent used for the chemical vapor transport (CVT) growth of MoTe2. The change in polarity sign with decreasing channel thickness may be associated with increasing role of surface states in ultra-thin layers, which in turn influence carrier concentration and dynamics in the channel due to modulation of Schottky barrier height and band-bending at the metal/semiconductor interface.

A novel rectangular shape differential CMOS split-drain Hall Effect magnetic field-effect transistor (MAGFET) was designed and fabricated employing a CMOS 0.5 μm process. The detection and monitoring of single 2.8 μm diameter magnetic beads was successfully performed using this MAGFET design. Based on the device modeling, simulation and the signal to noise ratio analysis, it was found that the optimal sensitivity can be achieved when the MAGFET channel width to length ratio is equal to 1.3. Further, it is shown through that when the MAGFET is scaled down, its SNR performance can sustain its peak, while being more sensitive to the geometry variations.

A flexible technology is proposed to integrate smart electronics and microfluidics all embedded in an elastomer package. The microfluidic channels are used to deliver both liquid samples and liquid metals to the integrated circuits (ICs). The liquid metals are used to realize electrical interconnects to the IC chip. This avoids the traditional IC packaging challenges, such as wire-bonding and flip-chip bonding, which are not compatible with current microfluidic technologies. As a demonstration we integrated a CMOS magnetic sensor chip and associate microfluidic channels on a polydimethylsiloxane (PDMS) substrate that allows precise delivery of small liquid samples to the sensor. Furthermore, the packaged system is fully functional under bending curvature radius of one centimetre and uniaxial strain of 15%. The flexible integration of solid-state ICs with microfluidics enables compact flexible electronic and lab-on-a-chip systems, which hold great potential for wearable health monitoring, point-of-care diagnostics and environmental sensing among many other applications.

We have demonstrated flexible packaging and integration of CMOS IC chips with PDMS microfluidics. Microfluidic channels are used to deliver both liquid samples and liquid metals to the CMOS die. The liquid metals are used to realize electrical interconnects to the CMOS chip. As a demonstration we integrated a CMOS magnetic sensor die and matched PDMS microfluidic channels in a flexible package. The packaged system is fully functional under 3cm bending radius. The flexible integration of CMOS ICs with microfluidics enables previously unavailable flexible CMOS electronic systems with fluidic manipulation capabilities, which hold great potential for wearable health monitoring, point-of-care diagnostics and environmental sensing.

A novel circular CMOS MAGFET (Magnetic Field Effect Transistor) design is introduced and a novel device geometry design methodology is proposed to optimize the magnetic particle detection sensitivity of such devices. In order to optimize the signal to noise ratio, it was determined that the geometry of the MAGFET is required to have specific ratios, where its sector angle θ and its inner and outer radii r 1 and r 2 are optimized when θ/ ln ( r 2 / r 1 ) = 1.3 . Compared to the more traditional rectangular MAGFET, the circular MAGFET has compatible SNR peak performance with rectangular MAGET. However, when the size of the MAGFET is scaled down in order to detect smaller magnetic particles, the proposed circular MAGFET has more robust SNR performance, design flexibility and tolerance to processing variations.

The development of a shear horizontal surface acoustic wave (SH-SAW) liquid sensor with identification (ID) for wireless applications is described. Moreover, a novel feature of "write capability" for this sensor is proposed. The SH-SAW passive sensor has a delay line configuration with a sensing area. The sensor is fabricated on a lithium tantalate (LiTaO3) substrate, which is Y-cut with rotations specified between about 36° around the X-axis. The principle of detection is based on the attenuation and time delay between the signals. The sensor is encoded according to partial reflections of an interrogation signal by metal reflectors placed on both side of the interdigital transducers (IDT). The structure of the sensor, the principle of the wireless communication, the detection process and testing results are presented.

A novel circular shape CMOS Hall Effect sensor design is proposed in this paper. Compared with traditional rectangular shape Hall Effect sensor, the proposed design can improve the sensitivity significantly. By implementing this sensor design with readout circuit, amplifier and DSP circuit in a CMOS chip, the Enzyme-Linked Immunosorbent Assay (ELISA) can be replaced by a lower cost, more portable and higher sensitive magnetic bead labeled immunoassay platform, which could eventually realize molecular diagnosis on chip.

Investigations of the static characteristics, responsivity, internal noises, and detectivity of the forward biased p-i-n photodetectors made on wide bandgap compensated semiconductors operating in double injection regime are presented. Noise related calculations are performed by utilizing "Impedance Field Method". Numerical simulations are made assessing 4H-SiC and GaN biased p-i-n photodiodes noise related characteristics. It is shown that forward biased p-i-n photodiodes have low level of thermal and generation-recombination noises and high values of sensitivity and detectivity at the room temperature.

The operation of a nonlinear binary detector with hysteresis is investigated. Prior models developed for continuous time inputs are extended for the computationally more efficient discrete-time inputs. The input to the rectangular hysteresis detector is modeled to be a binary signal in the presence of additive independent identically distributed noise. The rectangular hysteresis loop models one of a number of rate independent repeaters in an optical communication link. The link is terminated by a binary discriminator that is tuned to a particular bit duration. The study shows that key calculations to compute the bit error probability can be performed by employing the formalism of discrete Markov chains.

In this paper we describe the design and implementation of a CMOS surface acoustic wave (SAW) oscillator. The oscillator utilizes surface acoustic wave resonators implemented in both 1.6micron and 0.5micron AMI CMOS process and fabricated through MOSIS. When connected to Pierce oscillator circuits, these resonators are capable of synthesizing frequencies in the range of 400MHz to 1GHz. This paper also addresses the design issues involving codesigning micromachined resonators with CMOS circuitry to optimize the oscillator design

Design of a CMOS compatible thin ZnO film base, and a LiNbO3 wafer base, Surface Acoustics Wave (SAW) gas sensors that are highly selective and sensitive are described. Furthermore, Design an post CMOS processing fabrication steps that utilizes micro-electro-mechanical systems (MEMS) techniques to implement SAW gas sensor is presented. Rayleigh wave velocity for various ZnO film thickness is simulated and results are presented. Velocity calculation is based on a computer simulation of multiplayer (ZnO/SiO2/Si) structure that uses wave equations. Simulation results and experimental measurements of SA W sensors with single layer bulk LiNbO3 wafer are shown, and compared. Moreover, results of experimentation and simulation of wave velocity for a yz-cut LiNbO3 wafer is shown.

ZnO, a well-known piezoelectric material, is used to develop micro-scale Surface Acoustic Wave (SAW) delay line sensor. In this work, SAW delay line Devices are fabricated employing ZnO films that are deposited by RF sputtering technique. Films are characterized prior to device fabrication by X-Ray Diffraction (XRD) for film crystalline quality, UV-visible transmission spectroscopy for optical characteristics, and Atomic Force Microscopy (AFM) for surface morphology. Interdigital electrodes producing surface acoustic waves in the hundreds of MHz are developed by photolithography and metalization techniques. SAW delay line device testing, measurement and characteristics on RF sputtered ZnO films are presented and compared.