Origin of multi-level switching and telegraphic noise in organic nanocomposite memory devices.

The origin of negative differential resistance (NDR) and its derivative intermediate resistive states (IRSs) of nanocomposite memory systems have not been clearly analyzed for the past decade. To address this issue, we investigate the current fluctuations of organic nanocomposite memory devices with NDR and the IRSs under various temperature conditions. The 1/f noise scaling behaviors at various temperature conditions in the IRSs and telegraphic noise in NDR indicate the localized current pathways in the organic nanocomposite layers for each IRS. The clearly observed telegraphic noise with a long characteristic time in NDR at low temperature indicates that the localized current pathways for the IRSs are attributed to trapping/de-trapping at the deep trap levels in NDR. This study will be useful for the development and tuning of multi-bit storable organic nanocomposite memory device systems

THz-Wave Waveguide Packaging with Multiple THz On-Chip Transitions Integrated in Single Chip

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THz-Wave Waveguide Packaging with Multiple THz On-Chip Transitions Integrated in Single Chip

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High-Yield Functional Molecular Electronic Devices

An ultimate goal of molecular electronics, which seeks to incorporate molecular components into electronic circuit units, is to generate functional molecular electronic devices using individual or ensemble molecules to fulfill the increasing technical demands of the miniaturization of traditional silicon-based electronics. This review article presents a summary of recent efforts to pursue this ultimate aim, covering the development of reliable device platforms for high-yield ensemble molecular junctions and their utilization in functional molecular electronic devices, in which distinctive electronic functionalities are observed due to the functional molecules. In addition, other aspects pertaining to the practical application of molecular devices such as manufacturing compatibility with existing complementary metal-oxide-semiconductor technology, their integration, and flexible device applications are also discussed. These advances may contribute to a deeper understanding of charge transport characteristics through functional molecular junctions and provide a desirable roadmap for future practical molecular electronics applications.OAIID:RECH_ACHV_DSTSH_NO:T201721462RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A078823CITE_RATE:13.709DEPT_NM:물리·천문학부EMAIL:[email protected]_YN:YN

An E-Band 21-dB Variable-Gain Amplifier with 0.5-V Supply in 40-nm CMOS

This paper presents a variable-gain amplifier (VGA) in the 68-78 GHz range. To reduce DC power consumption, the drain voltage was set to 0.5 V with competitive performance in the gain and the noise figure. High-Q shunt capacitors were employed at the gate terminal of the core transistors to move input matching points for easy matching with a compact transformer. The four stages amplifier fabricated in 40-nm bulk complementary metal oxide semiconductor (CMOS) showed a peak gain of 24.5 dB at 71.3 GHz and 3-dB bandwidth of more than 10 GHz in 68-78 GHz range with approximately 4.8-mW power consumption per stage. Gate-bias control of the second stage in which feedback capacitances were neutralized with cross-coupled capacitors allowed us to vary the gain by around 21 dB in the operating frequency band. The noise figure was estimated to be better than 5.9 dB in the operating frequency band from the full electromagnetic (EM) simulation.11Ysciescopu

Active offset-frequency control of optical frequency comb via sum-frequency mixing of passively mode-locked laser and continuous-wave laser

Abstract We propose a method for actively controlling the frequency of an optical frequency comb (OFC) using sum-frequency generation (SFG) with a nonlinear crystal. For the first time, OFC generation was experimentally demonstrated via sum-frequency mixing of a narrowband continuous wave (CW) laser and a passively mode-locked fiber laser. By adjusting the optical frequency of the CW laser, we successfully controlled the offset-frequency of the SFG-OFC, which was mapped from the OFC of the pulse pump laser. Furthermore, by comparing the spectral widths of the SFG-OFC modes generated from two CW lasers with different spectral widths, we confirmed that the spectral characteristics of the SFG-OFC modes depended on the spectral features of the CW laser

Three-Terminal Single-Molecule Junctions Formed by Mechanically Controllable Break Junctions with Side Gating

Molecules are promising candidates for electronic device components because of their small size, chemical tunability, and ability to self-assemble. A major challenge when building molecule-based electronic devices is forming reliable molecular junctions and controlling the electrical current through the junctions. Here, we report a three-terminal junction that combines both the ability to form a stable single-molecule junction via the mechanically controllable break junction (MCBJ) technique and the ability to shift the energy levels of the molecule by gating. Using a noncontact side-gate electrode located a few nanometers away from the molecular junction, the conductance of the molecule could be dramatically modulated because the electrical field applied to the molecular junction from the side gate changed the molecular electronic structure, as confirmed by the ab initio calculations. Our study will provide a new design for mechanically stable single-molecule transistor junctions fabricated by the MCBJ method

Flexible Molecular-Scale Electronic Devices Composed of Diarylethene Photoswitching Molecules

The electrical properties of diarylethene photoswitching molecular devices on flexible substrates are studied. When exposed to UV or visible light, diarylethene molecular devices show two electrical states (a high and a low conductance state) with a discrepancy of an order of magnitude in the level of current between the two states. The diarylethene flexible molecular devices exhibit excellent long-time stability and reliable electrical characteristics in both conductance states when subjected to various mechanical stresses

Statistical Analysis of Electrical Properties of Octanemonothiol versus Octanedithol in PEDOT:PSS-Electrode Molecular Junctions

We fabricated a large number of octanemonothiol (C8) and octanedithol (DC8) molecular electronic devices with PEDOT:PSS (3,4-ethylenedioxythiophene) interlayer and performed a statistical analysis on the electronic properties of these devices. From the analysis, we obtained the Gaussian plot of histograms of Logic, (current density (J)) and several statistical estimates such as arithmetic mean, median, Gaussian mean, arithmetic standard deviation, adjusted absolute median deviation, and Gaussian standard deviation. We determined the current density-voltage (J-V) characteristics from the statistically representative data for C8 and DC8 devices and found that the conductivity of C8 is higher than that of DC8 by a factor of similar to 10. The difference of the conductivity of C8 and DC8 devices is attributed to the difference of the contact properties between the C8 and DC8 PEDOT:PSS-interlayer molecular junctions