There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

An introduction to heat transfer

International Technology Roadmap for Semiconductors 2003の要求清浄度について － シリコンウエハ表面と雰囲気環境に要求される清浄度, 分析方法の現状について －

The stability of two-dimensional (2D) layers and membranes is subject of a long standing theoretical debate. According to the so called Mermin-Wagner theorem, long wavelength fluctuations destroy the long-range order for 2D crystals. Similarly, 2D membranes embedded in a 3D space have a tendency to be crumpled. These dangerous fluctuations can, however, be suppressed by anharmonic coupling between bending and stretching modes making that a two-dimensional membrane can exist but should present strong height fluctuations. The discovery of graphene, the first truly 2D crystal and the recent experimental observation of ripples in freely hanging graphene makes these issues especially important. Beside the academic interest, understanding the mechanisms of stability of graphene is crucial for understanding electronic transport in this material that is attracting so much interest for its unusual Dirac spectrum and electronic properties. Here we address the nature of these height fluctuations by means of straightforward atomistic Monte Carlo simulations based on a very accurate many-body interatomic potential for carbon. We find that ripples spontaneously appear due to thermal fluctuations with a size distribution peaked around 70 \AA which is compatible with experimental findings (50-100 \AA) but not with the current understanding of stability of flexible membranes. This unexpected result seems to be due to the multiplicity of chemical bonding in carbon.

Intrinsic ripples in graphene

Magnetocaloric effect: From materials research to refrigeration devices

In this paper a complete surface potential-based core model for the undoped symmetric double-gate MOSFETs is derived from a fully self-consistent coupling between the surface potential versus voltage equation from Poisson equation solution and the drain current expression from Pao-Sah's double integral. The model consists of a single set of the surface potential equation and the analytic drain current in terms of the surface potential evaluated at the source and drain ends. The presented model is verified by extensive comparison with the 2-D numerical simulation for different operation regions and geometry parameters, demonstrating the model accuracy and prediction capability.

A Complete Surface Potential-Based Core Model for the Undoped Symmetric Double-Gate MOSFETs

A charge-based silicon nanowire FET (SNWT) compact model has been developed. For the first time, inversion charge of SNWT with arbitrary doping concentration is described by an accurate equation including the effects of doping and volume inversion. Analytic drain current, transconductance, output conductance, terminal charges and capacitance are all physically derived and compared with numerical simulation. It shows that the core model is valid for all operation regions and a wide range of physical configuration including channel doping concentrations and geometrical dimensions. Moreover, advanced physical effects have been included in the model self-consistently.

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A complete charge based compact model for silicon nanowire FETs including doping and advanced physical effects

Using optical wireless communications for sensors enables low power and small size of the nodes, such as smart dusts. This paper proposes a passive optical transmitter for smart dusts. Two liquid crystal (LC) modulator circuits have been designed for the switching the liquid crystal cells in the transmitter. The circuits are fabricated using a standard $0.18\mu \mathrm{m}$ CMOS process. Measurement results show that they can work under 0. 5V supply and successfully do the switching as designed. The transmission data rate can be 10bps, which is limited by the response speed of the LC cell.

A Passive Optical Transmitter Using LC Switches for IoT Smart Dusts

This paper reports a new Reaction-Diffusion (R-D) model derived from ultra-fast measurements of the negative bias temperature instability (NBTI) effect. The reaction of Si-H bonds at the Si/SiO2 interface dominates the short term effect while H2 diffusion in poly gate responses for long term degradation. The developed R-D model breaks through the limitation of discontinuous time exponent approaches in the classical R-D models for simulating short and long term NBTI effects, and matches well with measured data over a wide range of stress time.

Compact Reaction-Diffusion Model for Accurate NBTI Prediction

An analytical model for detection of terahertz radiation by plasma wave in cylindrical surrounding-gate (SRG) MOSFETs is presented. In comparison with traditional drain-current models, the rectification response of terahertz signal due to current self-mixing in conducting channel is considered by solving coupled plasma fluid equations using perturbation method. The resulted model is for the first time dipicting detector response in above threshold, near threshold and subthreshold regimes by a single expression valid for both resonant and nonresonant detection schemes. As no fitting parameters is adopted, the model is physical and predicative. Model validity has been extensively verified through numerically solving differential equations with a wide range of incident wave frequencies, channel doping concentrations, device working temperatures, SRG MOSFET geometry parameters as well as incident wave amplitudes. Model applicability to large input terahertz signal has also been discussed. The presented model is convenient for finding the optimum detector design from a multiparameter space. Its great universality will make it a candidate compact model for future terahertz integrated circuit simulation.An analytical model for detection of terahertz radiation by plasma wave in cylindrical surrounding-gate (SRG) MOSFETs is presented. In comparison with traditional drain-current models, the rectification response of terahertz signal due to current self-mixing in conducting channel is considered by solving coupled plasma fluid equations using perturbation method. The resulted model is for the first time dipicting detector response in above threshold, near threshold and subthreshold regimes by a single expression valid for both resonant and nonresonant detection schemes. As no fitting parameters is adopted, the model is physical and predicative. Model validity has been extensively verified through numerically solving differential equations with a wide range of incident wave frequencies, channel doping concentrations, device working temperatures, SRG MOSFET geometry parameters as well as incident wave amplitudes. Model applicability to large input terahertz signal has also been discussed. The presented model ...

Jin He

Papers

A Complete Surface Potential-Based Core Model for the Undoped Symmetric Double-Gate MOSFETs

A complete charge based compact model for silicon nanowire FETs including doping and advanced physical effects

A Passive Optical Transmitter Using LC Switches for IoT Smart Dusts

Compact Reaction-Diffusion Model for Accurate NBTI Prediction

An analytical model for terahertz detection in cylindrical surrounding-gate MOSFETs