scholarly journals Physical-Based Simulation of the GaN-Based Grooved-Anode Planar Gunn Diode

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 97 ◽  
Author(s):  
Ying Wang ◽  
Liu-An Li ◽  
Jin-Ping Ao ◽  
Yue Hao

In this paper, a novel gallium nitride (GaN)-based heterostructure Gunn diode is proposed for the first time to enhance the output characteristics of Gunn oscillation waveforms. A well-designed grooved anode contact is adopted to separate the long-channel diode into two short-channel diodes in parallel. If the grooved anode contact is positioned in the middle of the device, the output power nearly doubles in the grooved-anode diode compared with the single-channel ones, as does the output frequency. Based on the numerical results, the best output characteristics are obtained at the 2.0-µm symmetrical grooved-anode diode, which produces nearly 5.48 mW of power at the fundamental frequency of 172.81 GHz, with 3.13% efficiency of power conversion. If the grooved anode contact is not positioned in the middle of the diode, the harmonic frequency would be enhanced. The GaN heterostructure grooved-anode Gunn diode has been demonstrated to be an excellent solid-state source of terahertz oscillator.

2008 ◽  
Vol 1 (2) ◽  
pp. 139-155 ◽  
Author(s):  
YAEL DARR

This article describes a crucial and fundamental stage in the transformation of Hebrew children's literature, during the late 1930s and 1940s, from a single channel of expression to a multi-layered polyphony of models and voices. It claims that for the first time in the history of Hebrew children's literature there took place a doctrinal confrontation between two groups of taste-makers. The article outlines the pedagogical and ideological designs of traditionalist Zionist educators, and suggests how these were challenged by a group of prominent writers of adult poetry, members of the Modernist movement. These writers, it is argued, advocated autonomous literary creation, and insisted on a high level of literary quality. Their intervention not only dramatically changed the repertoire of Hebrew children's literature, but also the rules of literary discourse. The article suggests that, through the Modernists’ polemical efforts, Hebrew children's literature was able to free itself from its position as an apparatus controlled by the political-educational system and to become a dynamic and multi-layered field.


2015 ◽  
Vol 1737 ◽  
Author(s):  
Rebecca Isseroff ◽  
Zhenhua Yang ◽  
Jessica Kim ◽  
Andrew Chen ◽  
Miriam Rafailovich

ABSTRACTIn this study, an “inverted” design, phase-separated morphology and gold-functionalized reduced graphene oxide (Au-rGO) were used to address exciton recombination and poor Fermi level alignment. To increase efficiencies, a unique methodology was used to coat Au-rGO on top of the active layer. When 0.05 Au-rGO was blended with the active layer, there were metal-thiolate bonds with P3HT and π-π stacking with PCBM. However, KPFM, measured for the first time for this material, showed that the while 0.05mM Au-rGO reduced the energy gap between P3HT and PBCM, this was offset by recombination. KPFM showed that Au-rGO may be better suited between the active layer and electrode. When 0.5mM Au-rGO was coated on top of the active layer, efficiency increased (p<0.002) nearly 600%, suggesting that Au-rGO is a more effective acceptor than a constituent of the active layer.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Md. Shahiduzzaman ◽  
Toshiharu Sakuma ◽  
Tetsuya Kaneko ◽  
Koji Tomita ◽  
Masao Isomura ◽  
...  

AbstractIn this study, a new, simple, and novel oblique electrostatic inkjet (OEI) technique is developed to deposit a titanium oxide (TiO2) compact layer (CL) on fluorine-doped tin oxide (FTO) substrate without the need for a vacuum environment for the first time. The TiO2 is used as electron transport layers (ETL) in planar perovskite solar cells (PSCs). This bottom-up OEI technique enables the control of the surface morphology and thickness of the TiO2 CL by simply manipulating the coating time. The OEI-fabricated TiO2 is characterized tested and the results are compared with that of TiO2 CLs produced by spin-coating and spray pyrolysis. The OEI-deposited TiO2 CL exhibits satisfactory surface coverage and smooth morphology, conducive for the ETLs in PSCs. The power-conversion efficiencies of PSCs with OEI-deposited TiO2 CL as the ETL were as high as 13.19%. Therefore, the present study provides an important advance in the effort to develop simple, low-cost, and easily scaled-up techniques. OEI may be a new candidate for depositing TiO2 CL ETLs for highly efficient planar PSCs, thus potentially contributing to future mass production.


Author(s):  
Ajay Kumar Singh

Purpose This study aims to develop a compact analytical models for undoped symmetric double-gate MOSFET based on carrier approach. Double-Gate (DG) MOSFET is a newly emerging device that can potentially further scale down CMOS technology owing to its excellent control of short channel effects, ideal subthreshold slope and free dopant-associated fluctuation effects. DG MOSFET is of two types: the symmetric DG MOSFET with two gates of identical work functions and asymmetric DG MOSFET with two gates of different work functions. To fully exploit the benefits of DG MOSFETs, the body of DG MOSFETs is usually undoped because the undoped body greatly reduces source and drain junction capacitances, which enhances the switching speed. Highly accurate and compact models, which are at the same time computationally efficient, are required for proper modeling of DG MOSFETs. Design/methodology/approach This paper presents a carrier-based approach to develop a compact analytical model for the channel potential, threshold voltage and drain current of a long channel undoped symmetric DG MOSFETs. The formulation starts from a solution of the 2-D Poisson’s equation in which mobile charge term has been included. The 2-D Poisson’s equation in rectangular coordinate system has been solved by splitting the total potential into long-channel (1-D Poisson’s equation) and short-channel components (remnant 2-D differential equation) in accordance to the device physics. The analytical model of the channel potential has been derived using Boltzmann’s statistics and carrier-based approach. Findings It is shown that the metal gate suppresses the center potential more than the poly gate. The threshold voltage increases with increasing metal work function. The results of the proposed models have been validated against the Technology Computer Aided Design simulation results with close agreement. Originality/value Compact Analytical models for undoped symmetric double gate MOSFETs.


2020 ◽  
Vol 8 (44) ◽  
pp. 23239-23247
Author(s):  
Andy Man Hong Cheung ◽  
Han Yu ◽  
Siwei Luo ◽  
Zhen Wang ◽  
Zhenyu Qi ◽  
...  

This is the first time alkylthio chains are employed on Y6-like NFAs to achieve organic solar cells of power conversion efficiency higher than 16%.


2013 ◽  
Vol 2 (1) ◽  
pp. 31 ◽  
Author(s):  
K. Sudhakar ◽  
R. Ananthakrishnan ◽  
A. Goyal ◽  
H.K. Darji

In this paper, a novel design of biomass battery has been introduced for providingelectricity to meet the lighting requirements of rural household using biomass. A biomass battery isdesigned, developed and tested using cow dung as the raw material. This is done via anaerobicdigestion of the cow dung, and power generation driven by the ions produced henceforth. Thevoltage and power output is estimated for the proposed system. It is for the first time that such ahigh voltage is obtained from cow dung fed biomass battery. The output characteristics of thisnovel battery design have also been compared with the previously designed battery.


2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Yasuo Koizumi ◽  
Hiroyasu Ohtake

A micropump was developed using boiling and condensation in a microchannel. The length and hydraulic diameter of the semi-half-circle cross-section microchannel having two open tanks at both ends were 26mm and 0.465mm, respectively. A 0.5×0.5mm2 electrically heated patch was located at the offset location from the center between both ends of the microchannel, at a distance of 8.5mm from one end and at a distance of 17mm from the other end. The microchannel and the two open tanks were filled with distilled water. The heating patch was heated periodically to cause cyclic formation of a boiling bubble and its condensation. By this procedure, flow from the short side (8.5mm side) to the long side was created. The flow rate increased as the heating rate was increased. The obtained maximum average flow velocity and flow rate were 10.4mm∕s and 2.16mm3∕s, respectively. The velocity of an interface between the bubble and the liquid plug during the condensing period was much faster than that during the boiling period. During the condensing period, the velocity of the interface at the short channel side (8.5mm side) was faster than that at the long channel side (17mm side). The equation of motion of liquid in the flow channel was solved in order to calculate the travel of liquid in the flow channel. The predicted velocities agreed well with the experimental results. The velocity differences between the short side and the long side, as well as those between the boiling period and the condensing period, were expressed well by the calculation. Liquid began to move from the stationary condition during both the boiling and the condensing periods. The liquid in the inlet side (short side) moved faster than that in the outlet side (long side) during the condensing period because the inertia in the short side was lower than that in the long side. Since the condensation was much faster than boiling, this effect was more prominent during the condensing period. By iterating these procedures, the net flow from the short side to the long side was created.


2002 ◽  
Vol 361 (2) ◽  
pp. 401-407 ◽  
Author(s):  
Sheila L. DARGAN ◽  
Edward J. A. LEA ◽  
Alan P. DAWSON

FK506-binding protein (FKBP12) is highly expressed in neuronal tissue, where it is proposed to localize calcineurin to intracellular calcium-release channels, ryanodine receptors and Ins(1,4,5)P3 receptors (InsP3Rs). The effects of FKBP12 on ryanodine receptors have been well characterized but the nature and function of binding of FKBP12 to InsP3R is more controversial, with evidence for and against a tight interaction between these two proteins. To investigate this, we incorporated purified type-1 InsP3R from rat cerebellum into planar lipid bilayers to monitor the effects of exogenous recombinant FKBP12 on single-channel activity, using K+ as the current carrier. Here we report for the first time that FKBP12 causes a substantial change in single-channel properties of the type-1 InsP3R, specifically to increase the amount of time the channel spends in a fully open state. In the presence of ATP, FKBP12 can also induce co-ordinated gating with neighbouring receptors. The effects of FKBP12 were reversed by FK506. We also present data showing that rapamycin, at sub-optimal concentrations of Ins(2,4,5)P3, decreases the rate of calcium release from cerebellar microsomes. These results provide evidence for a direct functional interaction between FKBP12 and the type-1 InsP3R.


2000 ◽  
Vol 622 ◽  
Author(s):  
O. Breitschädel ◽  
L. Kley ◽  
H. Gräbeldinger ◽  
B. Kuhn ◽  
F. Scholz ◽  
...  

ABSTRACTWe report on our progress on the fabrication of AlGaN/GaN HEMTs with extremely short gate length. AlGaN/GaN HEMTs with different gate length from 6 νm down to 60nm were fabricated to investigate DC- and high frequency behavior as well as short channel effects. We have found that the transistors with gates in the 100 nm range can be improved in the device performance with respect to transconductance and high frequency but shows also short channel effects as the loss of saturation in the output characteristics and a strong dependency of the threshold voltage on the gate length.


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