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The antenna-coupled microbolometer with suspended titanium heater and thermistor was attractive as a terahertz (THz) detector due to its structural simplicity and low noise levels. In this study, we attempted to improve the responsivity and noise-equivalent power (NEP) of the THz detector by using high-resistance heater stacked on the meander thermistor. A wide range of heater resistances were prepared by changing the heater width and thickness. It was revealed that the electrical responsivity and NEP could be improved by increasing the heater's resistance. To make the best use of this improvement, a high-impedance folded dipole antenna was introduced, and the optical performance at 1 THz was found to be better than that of the conventional halfwave dipole antenna combined with a low-resistance heater. Both the electrical and optical measurement results indicated that the increase in heater resistance could reduce the thermal conductance in the detector, thus improved the responsivity and NEP even if the thermistor resistance was kept the same. [ABSTRACT FROM AUTHOR]

Light enhancement occurs strongly within the plasmonic clusters by interaction with surface plasmons. Surface-enhanced Raman spectroscopic (SERS) characteristics of a series of silver@silica trimer core–shell (CS) nanosphere (NS) clusters are investigated in this paper. It is significant to understand the electric field (EF) enhancement mechanism behind the SERS technique. The effect of symmetry breaking is studied for the series starting from the highly symmetric trimer cluster and transformed to linear dimer geometry which progresses through the gradual reduction in the vertex NS. The optical activity such as the evolution of LSPR peak is discussed, the formation of hot spots is demonstrated and the strength of the local EF enhancement is calculated and correlated with the plasmon dipolar modes by using plasmon hybridization theory to understand the underlying physical concepts. [ABSTRACT FROM AUTHOR]

A novel measurement system consisting of scanning electron microscopy and infrared (IR) thermography has been constructed to measure the thermal conductivity and the thermal diffusivity on a micro-/nanometer scale. In this study, we measured them for a stainless-steel wire with a diameter of 50 μm to demonstrate the validity of our system. The time evolution of temperature distribution on the whole of the stainless-steel wire was recorded by the IR thermograph when the wire was irradiated by the electron beam (EB). A time response of the wire temperature corresponding to the on/off of the EB irradiation was clearly observed, indicating that local EB heating was realized. In addition, the experimental time evolution of temperature at its transient phenomena was in good agreement with the theoretical calculation based on a one-dimensional (1D) equivalent-circuit model of heat flow coupled with electric current, where the thermal parameters, such as thermal conductivity and heat capacitance, were set to bulk values. Therefore, it can be concluded that our system is valid to evaluate the thermal conductivity of the 1D wire sample. For evaluating the thermal diffusivity of the wire sample, we applied a periodic EB irradiation by a rectangular wave with a frequency of 0.25 Hz. The thermal diffusivity was evaluated to be (2.8 ± 0.6) × 10−5 m2 s−1, which was seven times as large as that of bulk stainless steel. Our system can be applied to an AC calorimetry method for a 1D system sample after the analysis procedure is further modified. [ABSTRACT FROM AUTHOR]

A core‐shell structure with CuO core and carbon quantum dots (CQDs) and carbon hollow nanospheres (CHNS) shell was prepared through facile in‐situ hydrothermal process. The composite was used for non‐enzymatic hydrogen peroxide sensing and electrochemical overall water splitting. The core‐shell structure was established from the transmission electron microscopy image analysis. Raman and UV‐Vis spectroscopy analysis confirmed the interaction between CuO and CQDs. The electrochemical studies showed the limit of detection and sensitivity of the prepared composite as 2.4 nM and 56.72 μA μM−1 cm−2, respectively. The core‐shell structure facilitated better charge transportation which in turn exhibited elevated electro‐catalysis towards hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting. The overpotential of 159 mV was required to achieve 10 mA cm−2 current density for HER and an overpotential of 322 mV was required to achieve 10 mA cm−2 current density for OER in 1.0 M KOH. A two‐electrode system was constructed for overall water splitting reaction, which showed 10 and 50 mA cm−2 current density at 1.83 and 1.96 V, respectively. The prepared CuO@CQDs@CHNS catalyst demonstrated excellent robustness in HER and OER catalyzing condition along with overall water splitting reaction. Therefore, the CuO@CQDs@CHNS could be considered as promising electro‐catalyst for H2O2 sensing, HER, OER and overall water splitting. [ABSTRACT FROM AUTHOR]

A common observation in metal-based (specifically, those with AlOx tunnel junctions) single-electron tunneling (SET) devices is a time-dependent instability known as the long-term charge offset drift. This drift is not seen in Si-based devices. Our aim is to understand the difference between these, and ultimately to overcome the drift in the metal-based devices. A comprehensive set of measurements shows that (1) brief measurements over short periods of time can mask the underlying drift, (2) we have not found any reproducible technique to eliminate the drift, and (3) two-level fluctuators (TLFs) in the metal-based devices are not stable. In contrast, in the Si-based devices the charge offset drifts by less than 0.01e over many days, and the TLFs are stable. We also show charge noise measurements in a SET device over four decades of temperature. We present a model for the charge offset drift based on the observation of nonequilibrium heat evolution in glassy materials, and obtain a numerical estimate in good agreement with our charge offset drift observations. We conclude that, while the Si devices are not perfect and defect-free, the defects are stable and noninteracting; in contrast, the interacting, unstable glasslike defects in the metal-based devices are what lead to the charge offset drift. We end by suggesting some particular directions for the improvement in fabrication, and in particular, fabrication with crystalline metal-oxide barriers, that may lead to charge offset drift-free behavior. [ABSTRACT FROM AUTHOR]

The ultimate goal of future information processing might be the realization of a circuit in which one bit is represented by a single electron. Such a challenging circuit would comprise elemental devices whose tasks are to drag, transfer, and detect single electrons. In achieving these tasks, the Coulomb blockade, which occurs in tiny conducting materials, plays an important role. This paper describes the current status of research on such single-charge-control devices from the viewpoints of circuit applications. [ABSTRACT FROM AUTHOR]

• Vanadium doped Molybdenum sulphide shows enormous potential for Hydrogen evolution. • Morphology of V- doped MoS 2 has been summarized. • Both acidic and basic medium electrocatalytic properties are discussed. • Flat band potential and donor density calculation from Mott-Schottky analysis. Two dimensional layered transition metal dichalcogenides (TMDS) have immense potential as inexpensive electro-catalyst for hydrogen evolution reaction (HER). Modification of crystal and electronic structure is a promising strategy to enhance the catalytic performance of TMDS. Herein, a colloquial solvothermal method was used to prepare the vanadium (V) doped MoS 2 (VMSd). The structural, morphological and chemical analysis confirmed the formation of highly pure and uniform VMSd nanoflower. Tuning of V content in MoS 2 successively improved its catalytic activity towards hydrogen evolution reaction (HER). As, evident from the polarization curve, the VMSd required low overpotential of 194 and 206 mV to achieve benchmarking current density of 10 mA cm−2 in acidic and basic medium, respectively. Mott-Schottky analysis suggested that the flat band potential of MoS 2 differed upon V-doping, resulting in alteration of charge transfer ability at the electrode-electrolyte interface. The Fermi level shifted towards the conduction band with optimized V-doping and the band structure got modified effectively. [ABSTRACT FROM AUTHOR]

We propose a planar device architecture compatible with the CMOS process technology as the optimal current benchmark of a Si-nanowire (NW) thermoelectric (TE) power generator. The proposed device is driven by a temperature gradient that is formed in the proximity of a perpendicular heat flow to the substrate. Therefore, unlike the conventional TE generators, the planar short Si-NWs need not be suspended on a cavity structure. Under an externally applied temperature difference of 5 K, the recorded TE power density is observed to be $12~\mu \text{W}$ /cm2 by shortening the Si-NWs length and suppressing the parasitic thermal resistance of the Si substrate. The demonstration paves a pathway to develop cost-effective autonomous internet-of-things applications that utilize the environmental and body heats. [ABSTRACT FROM AUTHOR]

The degradation of high-frequency characteristics of a 1.0-THz double-drift region (DDR) impact avalanche transit time (IMPATT) diode based on wurtzite gallium nitride (Wz-GaN), due to the influence of parasitic series resistance, has been investigated. A two-dimensional (2-D) large-signal (L-S) simulation method based on a non-sinusoidal voltage excitation (NSVE) model has been used for this purpose. A comprehensive model of series resistance has been developed by considering the influence of skin effect, and the said model has been incorporated in the 2-D L-S simulation for studying the effect of RF power output and DC to RF conversion efficiency of the device. Results indicate 24.2-35.9% reduction in power output and efficiency due to the RF power dissipation in the positive series resistance. However, the device can still deliver 191.7-202.9 mW peak RF power to the load at 1.0 THz with 8.48-6.41% conversion efficiency. GaN IMPATT diodes are capable of generating higher RF power at around 1 THz than conventional diodes, but the effect of parasitic series resistance causes havoc reduction in power output and efficiency. The nature of the parasitic resistance is studied here in the level of device fabrication and optimization, which to our knowledge is not available at present. [ABSTRACT FROM AUTHOR]

A band gap of ∼2.1 eV was obtained through the hybridization of reduced graphene oxide (rGO) with insulating hexagonal boron nitride (h-BN). The h-BN/rGO superlattice behaved like n type semiconductor due to the enriched electron density at the conduction band and allowed charge transfer depending on the redox potential of the electrolyte. The band gap energy was further minimized to ∼1.79 eV through fluorine (F) doping within the h-BN/rGO. F doping created population density near the valance band and the Fermi level shifted towards the lower energy level. F doped superlattice behaved like p type semiconductor where F was adsorbed mostly at the N site. It is noticed that the contribution of the redox charge transfer to the overall capacitance was increased in comparison to the electrochemical double layer capacitance with increasing F doping. The formation of defects and disorder due to doping provided facile diffusion path enhancing the charge storage contribution from the interior site of the electrode materials. The specific capacitance of the F doped h-BN/rGO superlattice was determined as 1250 F g −1 which is 130% of un-doped sample. An asymmetric supercapacitor (ASC) cell was fabricated with F doped h-BN/rGO superlattice, which showed almost zero IR drop, high stability (∼77% retention of capacitance after 10,000 charge–discharge cycles) and large energy and power density of 87.5 W h kg −1 and 6300 W kg −1 , respectively. Furthermore, the ASC also exhibited very low relaxation time constant of ∼0.39 ms ensuring effective power delivery and quick charge–discharge capacity. [ABSTRACT FROM AUTHOR]

Microbolometer is a radiation detector for infrared (IR) and terahertz (THz) waves. The temperature coefficient of resistance (TCR) of the thermistor is a vital factor, as the responsivity is proportional and noise equivalent power (NEP) is inversely proportional to it. The narrow-width effect on TCR and resistivity on two different substrates (SiO 2 /Si and SiN X /SiO 2 /Si) for platinum (Pt) and titanium (Ti) thermistor with various design width (DW) = 0.1–5 μm are investigated. Increased resistivity and reduced TCR of the devices with the decreased line width, is observed commonly for both metal and fitted with empirical formulae, which hold well for different substrates. It is evident from electron backscatter diffraction (EBSD) results showing reduced average grain size form Ti film to Ti nanowire (DW = 0.1 μm), that the reduced TCR is not dependent on crystal orientation or phase variation of material but can be correlated with reduced grain size due to reduction of width. The optimum value considering design requirement, thermistor of DW = 0.1 μm and 0.2 μm is used further for the fabrication of microbolometers. It is found that the device with DW = 0.1 μm of Ti thermistor has ∼1.5 times higher electrical responsivity (376 V/W) at maximum allowable current than that with DW = 0.2 μm (254 V/W), which is also ∼11 times higher than device with DW = 0.1 μm of Pt thermistor. [ABSTRACT FROM AUTHOR]

An optimized two-step electrochemical deposition technique for the synthesis of a Cu2O/graphene platelet composite from copper acetate and a graphite rod is demonstrated. In the first step, graphene nanoplatelets were electrodeposited onto a stainless steel substrate from the graphite rod and then Cu2O NPs from copper acetate solution were electrodeposited onto the same electrode through the second electrodeposition step. Raman spectroscopy and X-ray photoelectron spectroscopy were performed to confirm the quality of the graphene nanoplatelets produced. X-ray diffraction studies revealed the successful formation of Cu2O nanoparticles. Transmission electron microscopy and field emission scanning electron microscopy were carried out to study the morphology, and the microscopic images revealed that the graphene surfaces were evenly anchored with Cu2O nanoparticles. The electrocatalytic behavior of the Cu2O/graphene platelet composite was analysed through cyclic voltammetry, differential pulse voltammetry and amperometric studies. The electrochemical studies revealed the utilization of the prepared material for non-enzymatic electrochemical sensing of H2O2. The amperometric studies showed the sensitivity and limit of detection of the prepared Cu2O/graphene platelet composite to be 52.8595 μA μM−1 cm−2 and 34.32 nM, respectively. [ABSTRACT FROM AUTHOR]

Assuming the use in antenna-coupled bolometers to detect terahertz wave, integrated heater and thermistor were fabricated with titanium (Ti) on a silicon (Si) substrate, and its electrical responsivity was investigated at room temperature. To establish the dependence of microbolometer's responsivity on sizes and material characteristics of the thermistor and heater, an analytical model was made to describe the temperature rise with current in thermally isolated heater and resultant increase in electrical resistance. Although the behavior of the heater resistance could be reproduced by the model successfully, the responsivity coincides only for a bolometer of short heater length, suggesting the effect of slow response speed of the long heaters. [ABSTRACT FROM AUTHOR]

Abstract: We fabricated a nanodot-array device with multiple input gates on a silicon-on-insulator (SOI) wafer by using a pattern-dependent oxidation method with multiple input gates, which embodies a new concept of a flexible single-electron device. Although the device can generate many logic functions owing to the capacitive coupling between dots and many gates, the complicated structural configuration makes it difficult to confirm the formation of the nanodot array. For further investigation of this kind of device to achieve higher functionality, it is important to demonstrate experimentally that the dot array is actually formed. We analyzed the oscillation-peak shift caused by the gate voltage change, and successfully determined the location of the dots that contributed to the experimentally observed oscillations. [Copyright &y& Elsevier]

Abstract: The single-electron device (SED) enables the control of electron motion on the level of an elementary charge. Single-charge transfer devices are special SEDs that enable single-electron transfer synchronized with the gate clock. They have the potential for extremely low transfer error rates and are expected to be building blocks for future information processing and electrical metrology. We have been pursuing the fabrication of Si-based SEDs using CMOS technology with the help of electron-beam lithography and have recently demonstrated the single-charge transfer devices. The devices are composed of one Si quantum dot sandwitched between two tiny MOS gates and can operate at much higher temperatures than those of former metal-based and compound-semiconductor-based devices. This opens up the possibility of the practical use of clocked single-charge transfer. [Copyright &y& Elsevier]

We present a pixel-level angle sensitive detector composed of silicon-on-insulator (SOI) photodiode (PD) stacked with a gold surface plasmon (SP) antenna to affect the direction of the incoming light. The surface plasmons are excited in the grating-type SP antenna and enhance the diffraction efficiency of the grating. The diffracted light is coupled strongly with the propagation light in the SOI waveguide when the phase matching condition is satisfied. The phase matching takes place at a specific angle of light incidence, and the discrimination of the light based on the incident angle is achieved. As spatial patterns in the polar coordinate of the elevation-azimuth angles (θ, ϕ) of the incident light, we present the phase matching condition theoretically, the absorption efficiency in the SOI by simulation, and also the quantum efficiency of the SOI PD experimentally for different SP antennas of one-dimensional (1D) line-and-space (L/S) and two-dimensional (2D) hole array gratings under various polarization angles. 1D grating offers a polarization sensitive angle detection and 2D grating exhibits angle detection in two orthogonal directions, enabling a polarization independent angle sensitivity. A good agreement among the theory, simulation, and experiment are attained. The proposed device features relatively high quantum efficiency as an angle-sensitive pixel (ASP) and gives wider opportunities in applications such as three-dimensional (3D) imaging, depth-of-field extension, and lensless imaging. [ABSTRACT FROM AUTHOR]

Plasmonic properties of trimer nanocluster depend on their geometric configuration. In this work, local electric field enhancement in the junction region of the trimer Ag@SiO 2 core-shell is investigated using three-dimensional electromagnetic simulation based on finite-difference time domain (FDTD) method. Plasmonic wavelength dependence for the two orthogonal polarizations is analyzed for different geometric configurations by gradually breaking the symmetry of the trimer nanospheres. The highly symmetric trimer in the form of equilateral triangle pattern possesses highly intense hotspots with the resonance wavelengths that are degenerate in nature. Breaking of this mode degeneracy occurs when the symmetric triangular pattern of the trimer is gradually transformed to a linear chain arrangement. Trimer core shell with linear chain symmetry exhibits the highest electromagnetic field enhancement which is nearly four times greater than the bare metal trimer but is very sensitive to polarization direction. The localized surface plasmon resonance (LSPR) is red shifted and blue shifted under longitudinal and transverse polarization, respectively. The LSPR shift and the electric field enhancement of the trimer nanocluster upon symmetry breaking under different polarization is compared and is explained using plasmon hybridization theory. The large polarization insensitive electric field enhancement exhibited by the symmetry core-shell may be employed for surface enhanced Raman spectroscopy based chemical and biological molecule detection. Unlabelled Image • FDTD analysis of electromagnetic enhancement at the junction of plasmonic core-shell trimer nanospheres. • Transformation in the geometric configurations of trimers allows tuning of resonance wavelength. • Correlation of light interaction with trimer's surface by plasmon hybridization theory with FDTD results. • Symmetry core-shell geometry exhibits as an optimized design for a highly sensitive SERS substrate. [ABSTRACT FROM AUTHOR]

Facile synthesis of carbon coated NiS 2 composite through one-step hydrothermal process was demonstrated. Three different composites were synthesized (NCC1, NCC2, and NCC3) by changing the stoichiometric ratio of nickel, sulphur and carbon precursor. The particle size and its distribution depend on the amount of carbon precursor and metal sulphides ratio. The carbon coating on metal sulphides significantly augmented the electrochemical properties of the supercapacitor electrodes. It was found that in an optimum ratio of carbon precursor and metal sulphide, the particles were formed uniformly as seen in the NCC2 composites and exhibited the specific capacitance of 2212 F g−1 at a specific current of 2 A g−1 in a three-electrode system. An asymmetric supercapacitor (ASC) device was fabricated with NCC2 as positive electrode and thermally reduced graphene oxide as negative electrode. The ASC device showed high specific capacitance of 184.9 F g−1 at 3 A g−1 and specific energy of 50.35 Wh Kg−1 at a specific power of ~2.26 kW kg−1. It showed ~83% retention in specific capacitance after 6000 charge-discharge cycles. High specific capacitance, specific energy and specific power of the ASC device confirmed that the NCC2 composite could be used as energy storage electrode materials for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Abstract: We propose a simple method for fabricating Si single-electron transistors (SET) with coupled dots by means of a pattern-dependent-oxidation (PADOX) method. The PADOX method is known to convert a small one-dimensional Si wire formed on a silicon-on-insulator (SOI) substrate into a SET automatically. We fabricated a double-dot Si SET when we oxidized specially designed Si nanowires formed on SOI substrates. We analyzed the measured electrical characteristics by fitting the measurement and simulation results and confirmed the double-dot formation and the position of the two dots in the Si wire. [Copyright &y& Elsevier]

In our pursuit of high-power terahertz (THz) wave generation, we propose innovative edge-terminated single-drift region (SDR) multi-quantum well (MQW) impact avalanche transit time (IMPATT) structures based on the Al x Ga 1- x N/GaN/Al x Ga 1- x N material system, with a fixed aluminum mole fraction of x = 0.3. Two distinct MQW diode configurations, namely p + -n junction-based and Schottky barrier diode structures, were investigated for their THz potential. To enhance reverse breakdown characteristics, we propose employing mesa etching and nitrogen ion implantation for edge termination, mitigating issues related to premature and soft breakdown. The THz performance is comprehensively evaluated through steady-state and high-frequency characterizations using a self-consistent quantum drift-diffusion (SCQDD) model. Our proposed Al 0.3 Ga 0.7 N/GaN/Al 0.3 Ga 0.7 N MQW diodes, as well as GaN-based single-drift region (SDR) and 3C-SiC/Si/3C-SiC MQW-based double-drift region (DDR) IMPATT diodes, are simulated. The Schottky barrier in the proposed diodes significantly reduces device series resistance, enhancing peak continuous wave power output to approximately 300 mW and DC to THz conversion efficiency to nearly 13% at 1.0 THz. Noise performance analysis reveals that MQW structures within the avalanche zone mitigate noise and improve overall performance. Benchmarking against state-of-the-art THz sources establishes the superiority of our proposed THz sources, highlighting their potential for advancing THz technology and its applications.

This study demonstrates the conversion of metallic titanium (Ti) to titanium oxide just by conducting electrical current through Ti thin film in vacuum and increasing the temperature by Joule heating. This led to the improvement of electrical and thermal properties of a microbolometer. A microbolometer with an integrated Ti thermistor and heater width of 2.7 µm and a length of 50 µm was fabricated for the current study. Constant-voltage stresses were applied to the thermistor wire to observe the effect of the Joule heating on its properties. Thermistor resistance ~14 times the initial resistance was observed owing to the heating. A negative large temperature coefficient of resistance (TCR) of -0.32%/K was also observed owing to the treatment, leading to an improved responsivity of ~4.5 times from devices with untreated Ti thermistors. However, this does not improve the noise equivalent power (NEP), due to the increased flicker noise. Microstructural analyses with transmission electron microscopy (TEM), transmission electron diffraction (TED) and energy dispersive X-ray (EDX) confirm the formation of a titanium oxide (TiO x ) semiconducting phase on the Ti phase (~85% purity) deposited initially, further to the heating. Formation of TiO x during annealing could minimize the narrow width effect, which we reported previously in thin metal wires, leading to enhancement of responsivity.

Aim: Further to our reports on chip-integrable uncooled terahertz microbolometer arrays, compatible with medium-scale semiconductor device fabrication processes, the possibility of the development of chip-integrable medical device is proposed here. Methods: The concept of graphene-based nanopatch antennas with design optimization by the finite element method (FEM) is explored. The high-frequency structure simulator (HFSS) utilized fine FEM solver for analyzing empirical mode decomposition preprocessing and for modeling and simulating graphene antennas. Results: Graphene nanopatch antennas exhibited tunable features with varying patch dimensions and dependence on substrate material permittivity. Conclusion: This work implements reconfigurable graphene nanopatch antenna compatible with terahertz microbolometer arrays. This design concept further develops on-chip medical devices for possible screening of cancer cell with terahertz image processing.

Assuming that the 0.6-μm silicon-on-insulator (SOI) complementary metal-oxide-semiconductor (CMOS) technology, different Si-based temperature sensors such as metal-oxide-semiconductor field-effect transistor (MOSFET) (n-channel and p-channel), pn-junction diode (with p-body doping and without doping), and resistors (n + or p + single crystalline Si and n + polycrystalline Si) were designed and characterized for its possible use in 1-THz antenna-coupled bolometers. The use of a half-wave dipole antenna connected to the heater end was assumed, which limited the integrated temperature sensor/heater area to be 15 × 15 µm. Our main focus was to evaluate the performances of the temperature sensor/heater part, and the optical coupling between the incident light and heater via an antenna was not included in the evaluation. The electrothermal feedback (ETF) effect due to the bias current was considered in the performance estimation. A comparative analysis of various SOI bolometers revealed the largest responsivity ( R v ) of 5.16 kV/W for the n-channel MOSFET bolometer although the negative ETF in MOSFET reduced the R v . The noise measurement of the n-channel MOSFET showed the NEP of 245 pW/Hz 1/2 , which was more than one order of magnitude smaller than that of the n + polycrystalline Si resistive bolometer (6.59 nW/Hz 1/2 ). The present result suggests that the n-channel MOSFET can be a promising detector for THz applications.

The intracellular circadian clock mechanisms are known to affect various substantial cellular machinery such as cell cycle progression, inflammatory response, apoptosis, and DNA repair. Cancer growth in various tissues is still under circadian control, which may be at least partly underlain by the survived connections between the intracellular machinery and the clock. Considering such findings, chronotherapy has been applied to cancer treatments, in which anti-cancer drugs are administered in scheduled circadian times so as to resolve the trade-off between damages against the normal and cancer cells. However, any effective administration strategy has not yet been established especially in a quantitative sense. In this study, we develop an automaton model of cell division cycle interacting with circadian clock and suffering from a probability of cell death. A cancer cell is modeled by shortening/ lengthening the cell division interval and a transition to motility state under starving condition. Population proliferating dynamics in 3D space are simulated under the diffusion of nutrient factor and the anti-cancer drugs from a vessel. The simulation results show that the drug administration schedule could differentiate the damages against proliferation of normal and cancer cells. This implies the existence of optimal timing for the drug administration, which could provide an efficient strategy of chronotherapeutic treatment of cancer.

Low-frequency noise and hole lifetime in silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) are analyzed, considering their use in photon detection based on single-hole counting. The noise becomes minimum at around the transition point between front- and back-channel operations when the substrate voltage is varied, and increases largely on both negative and positive sides of the substrate voltage showing peculiar Lorentzian (generation-recombination) noise spectra. Hole lifetime is evaluated by the analysis of drain current histogram at different substrate voltages. It is found that the peaks in the histogram corresponding to the larger number of stored holes become higher as the substrate bias becomes larger. This can be attributed to the prolonged lifetime caused by the higher electric field inside the body of SOI MOSFET. It can be concluded that, once the inversion channel is induced for detection of the photo-generated holes, the small absolute substrate bias is favorable for short lifetime and low noise, leading to high-speed operation.

We report the effect of low-energy (1 keV) electron beam irradiation on gated, three-terminal devices constructed from metallic single-walled carbon nanotubes. Pristine devices, which exhibited negligible gate voltage response at room temperature and metallic single-electron transistor characteristics at low temperatures, when exposed to an electron beam, exhibited ambipolar field effect transistor (room temperature) and single-electron transistor (low temperature) characteristics. This metal-semiconductor transition is attributed to inhomogeneous electric fields arising from charging during electron irradiation.