Negative bias temperature instability has become an important reliability concern for ultra-scaled Silicon IC technology with significant implications for both analog and digital circuit design. In this paper, we construct a comprehensive model for NBTI phenomena within the framework of the standard reaction-diffusion model. We demonstrate how to solve the reaction-diffusion equations in a way that emphasizes the physical aspects of the degradation process and allows easy generalization of the existing work. We also augment this basic reaction-diffusion model by including the temperature and field-dependence of the NBTI phenomena so that reliability projections can be made under arbitrary circuit operating conditions.

Single molecule sensors in which nanoscale pores within biological or artificial membranes act as mechanical gating elements are very promising devices for the rapid characterization and sequencing of nucleic acid molecules. The two terminal electrical measurements of translocation of polymers through single ion channels and that of ssDNA molecules through protein channels have been demonstrated, and have sparked tremendous interest in such single molecule sensors. The prevailing view regarding the nanopore sensors is that there exists no electrical interaction between the nanopore and the translocating molecule, and that all nanopore sensors reported to-date, whether biological or artificial, operate as a coulter-counter, i.e., the ionic current measured across the pore decreases (is mechanically blocked) when the DNA molecule transverses through the pore. We have fabricated nanopore "channel" sensors with a silicon oxide inner surface, and our results challenge the prevailing view of exclusive mechanical interaction during the translocation of dsDNA molecules through these channels. We demonstrate that the ionic current can actually increase due to electrical gating of surface current in the channel due to the charge on the DNA itself.As a first step toward the ultimate goal of single-molecule DNA sequencing using nanopore sensors, one must first identify the key mechanical and electrical variables that control the translocation of the molecules through the nanopores. First, a nanopore used for characterization and sequencing of a single molecule must have a diameter of less than the persistence length (∼50 nm for dsDNA) to avoid any signal averaging from thermally induced conformational changes. Second, the pores must be chemically stable and mechanically robust under a wide variety of conditions of use. Third, and finally, the mechanical and electrical interaction between the nanopores and the single molecules must be well characterized. Toward this end, the electrical detection of translocation of polymers through single ion channels has been demonstrated. 1-2 Subsequently, the pioneering studies of the use of R-hemolysin protein pore within a lipid bilayer for the translocation of single strands of DNA molecules using a voltage bias across the membranes sparked tremendous interest in such single molecule sensors. [3][4][5][6][7][8] The normal ionic current through the protein pore in a lipid bilayer would detectably reduce as a polyanionic chain of ssDNA molecules traversed through the pore, even allowing the distinction between polycytosine and polyadenine molecules, thus demonstrating the potential of single base discrimination in these sensors. 4,5 Despite these advantages, robust integration of these biological sensors within practical devices is quite problematic, and a mechanical pore 9,10 provides numerous advantages over biological pores. Besides the obvious advantages of being able to drastically change ambient conditions such as pH, electric field, and temperature without distorting the s...

Flavonoids are important natural compounds with diverse biologic activities. Citrus flavonoids constitute an important series of flavonoids. Naringin and its aglycone naringenin belong to this series of flavonoids and were found to display strong anti-inflammatory and antioxidant activities. Several lines of investigation suggest that naringin supplementation is beneficial for the treatment of obesity, diabetes, hypertension, and metabolic syndrome. A number of molecular mechanisms underlying its beneficial activities have been elucidated. However, their effect on obesity and metabolic disorder remains to be fully established. Moreover, the therapeutic uses of these flavonoids are significantly limited by the lack of adequate clinical evidence. This review aims to explore the biologic activities of these compounds, particularly on lipid metabolism in obesity, oxidative stress, and inflammation in context of metabolic syndrome.

A simple analytical model, based on reaction-diffusion theory, is developed to predict the trade-off between average response (settling) time (ts) and minimum detectable concentration (ρ0) for nanobiosensors and nanochemical sensors. The model predicts a scaling relationship ρ0tsMD∼kD, where MD and kD are dimensionality dependent constants for one, two, and three dimensional nanosensors. We explore the performance limits of nanosensors using this analytical model and support its conclusions using detailed numerical simulation. Our results have obvious and significant implications for analyte density and response time reported in the literature and for design consideration of nanobiosensors and nanochemical sensors.

Gate-modulated transport through partially aligned films of single-walled carbon nanotubes (SWNTs) in thin film type transistor structures are studied experimentally and theoretically. Measurements are reported on SWNTs grown by chemical vapor deposition with systematically varying degrees of alignment and coverage in transistors with a range of channel lengths and orientations perpendicular and parallel to the direction of alignment. A first principles stick-percolation-based transport model provides a simple, yet quantitative framework to interpret the sometimes counterintuitive transport parameters measured in these devices. The results highlight, for example, the dramatic influence of small degrees of SWNT misalignment on transistor performance and imply that coverage and alignment are correlated phenomena and therefore should be simultaneously optimized. The transport characteristics reflect heterogeneity in the underlying anisotropic metal-semiconductor stick-percolating network and cannot be reproduced by classical transport models.

We present a MoS2 biosensor to electrically detect prostate specific antigen (PSA) in a highly sensitive and label-free manner. Unlike previous MoS2-FET-based biosensors, the device configuration of our biosensors does not require a dielectric layer such as HfO2 due to the hydrophobicity of MoS2. Such an oxide-free operation improves sensitivity and simplifies sensor design. For a quantitative and selective detection of PSA antigen, anti-PSA antibody was immobilized on the sensor surface. Then, introduction of PSA antigen, into the anti-PSA immobilized sensor surface resulted in a lable-free immunoassary format. Measured off-state current of the device showed a significant decrease as the applied PSA concentration was increased. The minimum detectable concentration of PSA is 1 pg/mL, which is several orders of magnitude below the clinical cut-off level of ~4 ng/mL. In addition, we also provide a systematic theoretical analysis of the sensor platform – including the charge state of protein at the specific pH level, and self-consistent channel transport. Taken together, the experimental demonstration and the theoretical framework provide a comprehensive description of the performance potential of dielectric-free MoS2-based biosensor technology.

The so-called Boltzmann tyranny defines the fundamental thermionic limit of the subthreshold slope of a metal-oxide-semiconductor field-effect transistor (MOSFET) at 60 mV dec at room temperature and therefore precludes lowering of the supply voltage and overall power consumption . Adding a ferroelectric negative capacitor to the gate stack of a MOSFET may offer a promising solution to bypassing this fundamental barrier . Meanwhile, two-dimensional semiconductors such as atomically thin transition-metal dichalcogenides, due to their low dielectric constant and ease of integration into a junctionless transistor topology, offer enhanced electrostatic control of the channel . Here, we combine these two advantages and demonstrate a molybdenum disulfide (MoS) two-dimensional steep-slope transistor with a ferroelectric hafnium zirconium oxide layer in the gate dielectric stack. This device exhibits excellent performance in both on and off states, with a maximum drain current of 510 μA μm and a sub-thermionic subthreshold slope, and is essentially hysteresis-free. Negative differential resistance was observed at room temperature in the MoS negative-capacitance FETs as the result of negative capacitance due to the negative drain-induced barrier lowering. A high on-current-induced self-heating effect was also observed and studied.

Materials that can serve as long-lived barriers to biofluids are essential to the development of any type of chronic electronic implant. Devices such as cardiac pacemakers and cochlear implants use bulk metal or ceramic packages as hermetic enclosures for the electronics. Emerging classes of flexible, biointegrated electronic systems demand similar levels of isolation from biofluids but with thin, compliant films that can simultaneously serve as biointerfaces for sensing and/or actuation while in contact with the soft, curved, and moving surfaces of target organs. This paper introduces a solution to this materials challenge that combines (i) ultrathin, pristine layers of silicon dioxide (SiO2) thermally grown on device-grade silicon wafers, and (ii) processing schemes that allow integration of these materials onto flexible electronic platforms. Accelerated lifetime tests suggest robust barrier characteristics on timescales that approach 70 y, in layers that are sufficiently thin (less than 1 μm) to avoid significant compromises in mechanical flexibility or in electrical interface fidelity. Detailed studies of temperature- and thickness-dependent electrical and physical properties reveal the key characteristics. Molecular simulations highlight essential aspects of the chemistry that governs interactions between the SiO2 and surrounding water. Examples of use with passive and active components in high-performance flexible electronic devices suggest broad utility in advanced chronic implants.