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51.
We present a study of the complex electronic behavior of a fullerene (C60) molecule attached to six leads (heterojunctions), which works as a three-dimension rectifier. In addition, we confirmed that the fullerene works not only as an electron donor, but also as barrier and transport channel to electrons through the molecule. Moreover, when the phenylpropanodinilla (PPP) lead is orthogonally subjected to bias voltage, the charge distribution and the current displays regions of saturation and resonance similar to semiconductor devices. In order to understand the electronic transport in the molecule, we applied non-equilibrium green function (NEGF) method and performed Fowler-Nordheim (FN) and Millikan-Lauritsen (ML) analyses. The ML curves proved to be sufficient to describe the FN characteristics. In this work, we report the theoretical design for electronic transport of a 3D device (6-terminal). 相似文献
52.
53.
Characterization of phosphorus implantation in 4H-SiC 总被引:3,自引:0,他引:3
V. Khemka R. Patel N. Ramungul T. P. Chow M. Ghezzo J. Kretchmer 《Journal of Electronic Materials》1999,28(3):167-174
We report the characterization of phosphorus implantation in 4H-SiC. The implanted layers are characterized by analytical
techniques (secondary ion mass spectrometry, transmission electron microscopy) as well as electrical and a sheet resistance
value as low as 160 Ω/□ has been measured. We have also studied the effect of annealing time and temperature on activation
of phosphorus implants. It has been shown to possible to obtain low sheet resistance (∼260 Ω/□) by annealing at a temperature
as low as 1200°C. High-dose (∼ 4 × 1015 cm−2) implants are found to have a higher sheet resistance than that on lower dose implants which is attributed to the near-surface
depletion of the dopant during high temperature anneal. Different implantation dosages were utilized for the experiments and
subsequently junction rectifiers were fabricated. Forward characteristics of these diodes are observed to obey a generalized
Sah-Noyce-Shockly multiple level recombination model with four shallow levels and one deep level. 相似文献
54.
对采用三电极气体间隙放电开关的脉冲功率电源和采用可控硅开关的脉冲功率电源进行了辐射电磁场测量与分析。所研究的脉冲功率电源的脉冲持续时间为ms量级,电流峰值为几十到几百kA。使用多组微分式磁场探头和高采样率、高存储深度的数字示波器进行了磁场测量;通过探头校对实验,对探头系数进行了校验。通过对微分测量结果的校正与积分运算,得到了磁场的时域波形。分析了低频段按照探头系数的计算方法和积分处理方法的关系,总结了时域波形重构的一些方法。得到了两种电源的电磁场特性:三电极气体间隙放电开关产生的磁场频谱范围可达10 MHz,而可控硅开关产生的磁场在1 MHz以内;其辐射电场微弱。 相似文献
55.
56.
Summary The paper describes tests for liquid chromatographs to assess the autosampler and pump flow rate precision; suitability of
the instrument for normal phase chromatography; UV detector performance; and external band broadening characteristics. Tests
for mixing and proportioning characteristics of solvent pumps and performance of diode array detectors are also considered.
These tests are designed to evaluate the performance of both newly released liquid chromatography equipment and equipment
already in operation. Data from evaluations carried out by instrument manufacturer’s and suppliers is reported and discussed.
This data offers specifications to a common format for initial selection of instruments prior to purchase. 相似文献
57.
B. G. M. Vandeginste G. Kateman J. K. Strasters H. A. H. Billiet L. de Galan 《Chromatographia》1987,24(1):127-134
Summary The mathematical resolution of overlapped chromatographic peaks obtained in HPLC with a diode array UV detector has received
considerable attention recently. The purpose of the proposed methods is the quantitation and identification of unknown solutes
in complex mixtures by an efficient use of all available data.
Basically two approaches have been proposed: the first one resolves the concentration profiles and calculates the pure spectra
by applying a minimal number of assumptions, which is denoted self-modeling-curve resolution. The second one is based on a
match of pure spectra available in a spectral library with the measured mixture spectra.
In this paper both approaches are evaluated with respect to their performance to provide the pure spectra and an accurate
quantitation of the concentrations. 相似文献
58.
A p-i-n diode for a Si1−xGex/Si single quantum well (SQW) electroluminescent (EL) device was successfully fabricated by solid-source (SS) and gas-source
(GS) “hybrid” Si molecular beam epitaxy (MBE). First, the undoped SQW layer was grown on a p-type Si(100) substrate by GSMBE
using disilane (Si2H6) and germane (GeH4). Then the n-type Si contact layer was regrown by SSMBE after transferring the sample through the air. A (2 × 1) reconstruction
was observed on a GSMBE-prepared Si surface even after the sample was exposed to air for 15 h. The excellent quality of the
EL p-i-n device was shown by the sharpest emission lines, ≈5.5 meV, ever reported in the EL spectra of an SiGe system. Linear
polarization along the SQW plane was also observed for no-phonon replica of EL. 相似文献
59.
A rubidium laser operating at 795 nm is optically pumped by a pulsed titanium sapphire laser to investigate the dynamics of Diode Pumped Alkali Lasers (DPALs). Linear scaling of output intensity for longitudinal excitation at intensities of 1.3-43 kW/cm2 and as much as 32 times threshold is observed. The slope efficiency depends directly on the number of absorbed photons for alkali concentrations of 0.8-2.0 × 1013 atoms/cm3 with no evidence for second order kinetics. The effective absorption cross section is reduced in part by the broad spectral width of the pump source relative to the pressure broadened lineshape. Spin orbit relaxation between the pumped and upper laser levels is sufficiently fast at 550 Torr of methane to prevent bottlenecking at all but the highest intensities. Comparison of laser characteristics with a quasi-two level analytic model suggests performance near the ideal steady-state limit, with the exception of modest mode matching. 相似文献
60.
Dr. Yuxuan Hu Dr. Jingsheng Miao Dr. Cheng Zhong Yang Zeng Prof. Shaolong Gong Dr. Xiaosong Cao Xue Zhou Dr. Yu Gu Prof. Chuluo Yang 《Angewandte Chemie (International ed. in English)》2023,62(19):e202302478
Heavy-atom integration into thermally activated delayed fluorescence (TADF) molecule could significantly promote the reverse intersystem crossing (RISC) process. However, simultaneously achieving high efficiency, small roll-off, narrowband emission and good operational lifetime remains a big challenge for the corresponding organic light-emitting diodes (OLEDs). Herein, we report a pure green multi-resonance TADF molecule BN-STO by introducing a peripheral heavy atom selenium onto the parent BN-Cz molecule. The organic light-emitting diode device based on BN-STO exhibited state-of-the-art performance with a maximum external quantum efficiency (EQE) of 40.1 %, power efficiency (PE) of 176.9 lm W−1, well-suppressed efficiency roll-off and pure green gamut. This work reveals a feasible strategy to reach a balance between fast RISC process and narrow full width at half maximum (FWHM) of MR-TADF by heavy atom effect. 相似文献