共查询到20条相似文献,搜索用时 187 毫秒
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在低温下,二极管正向压降是随着温度的降低而增加.早在六十年代初期,利用二极管的这一特性,探索低温测温技术就已引起人们的广泛兴趣.1966年GaAs二极管温度计进入了商品市场.为低温测量、控温技术增添了新的内容。 人们通常认为.GaAs二极管温度计的优点为(1)量程宽(1—400K),(2)受磁场影响不大.但是,有的GaAs二极管在30K下灵敏度不高,有的在10—20K有一灵敏度的 相似文献
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X波段超导前端组件应用于高灵敏度接收机,选频放大微弱信号,抑制发射泄露信号干扰,能够显著提高接收机的灵敏度和抗干扰能力。该组件主要包括三种器件:高温超导滤波器、低温低噪声放大器和低温隔离器。组件在15K温度平台下,主要性能指标为:等效噪声温度小于13K,增益31dB,发射频率抑制度大于110dB,承受阻带连续波功率3W,输入输出驻波比均小于1.25。 相似文献
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由铒和钕注入的ZnSe单晶所制备的发光二极管有很好的电致发光.这些二极管的外能量效率大约为5×10-5W/W,并且可以在很低电压下和低温下(77K)工作.这些二极管发射光谱显示了三价稀土离子饵和汝的特征辐射. 相似文献
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P. F. Goldsmith H. R. Fetterman B. J. Clifton C. D. Parker N. R. Erickson 《International Journal of Infrared and Millimeter Waves》1981,2(5):915-924
We report here the first results obtained by cooling a submillimeter quasioptical mixer, utilizing a Schottky diode in a corner reflector mixer structure. Measurements have been carried out at a wavelength of 434 microns. The diode inverse slope parameter Vo at low current decreases by a factor of 3 upon cooling to 50 K while the minimum system noise temperature of 5600 K (SSB), including the IF contribution, demonstrates a reduction of approximately 40% from the ambient temperature value. We also report improved system noise temperatures at 184 m and 119 m wavelengths of 38000 K and 64000 K (SSB), respectively.This work was supported by the Army Research Office and the Air Force Office of Scientific Research 相似文献
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采用4只HSMS 282肖特基二极管阵列,对大功率微波整流电路进行了研究。构造了基于微带线结构的2.45 GHz高效微波整流电路,将微波整流单元电路的输入功率提升到33 dBm。仿真和实验结果表明,在一定微波输入功率的条件下,整流电路在负载较大范围内变化时保持了高整流效率。通过在不同微波输入功率和负载下进行测量,发现当输入微波功率为27.0~31.7 dBm之间变化时,最高整流效率均达到了60%以上,当微波输入功率为30 dBm时,微波整流电路效率达到了63.3%。 相似文献
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W. Jantsch S. Lanzerstorfer L. Palmetshofer M. Stepikhova H. Preier 《Journal of luminescence》1998,80(1-4):9-17
At low temperatures, Er in Si produces a big variety of spectra in the 1.5 μm region which can be identified by high-resolution spectroscopy as being due to either interstitial Er or different complexes of Er with oxygen, intrinsic defects and other light impurities. Although the luminescence yield can be improved by codoping with light elements (C, N, O, F, etc.) all of these centres show strong thermal quenching of the luminescence above 150–200 K. There is, however, one type of rather broad spectrum in heavily Er- and O- doped Si, which is seen up to temperatures of 400 K and above. This spectrum can be excited in Si by hot electrons generated in a reverse biased diode. The same spectrum appears also in other Si related materials like porous Si and in silica with the same temperature dependence. In these materials, excitation spectroscopy is possible and it shows also close agreement of the excitation spectra. From these findings we infer that Er is incorporated in another surrounding and we propose Si–Er–O nano-precipitates since the spectra of other candidates, like Er2O3, are clearly different. We review recent work on the excitation and quenching mechanisms and we discuss consequences for technology. 相似文献
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物理实验中,二极管是最常用的电子元器件。教学中为了让学生理解二极管的特性和使用,借助于Protues软件设计了二极管特性实验仿真教学。通过仿真波形图或实时效果图示,使学生理解利用普通二极管的单向导电特性做整流电路,将交流电变换成直流电,稳压二极管能够稳定输出电压,发光二极管发出亮光,能够显示图形符号,传递信息。 相似文献
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K. Ding Y. P. Zeng X. C. Wei Z. C. Li J. X. Wang H. X. Lu P. P. Cong X. Y. Yi G. H. Wang J. M. Li 《Applied physics. B, Lasers and optics》2009,97(2):465-468
The electroluminescence efficiency at room temperature and low temperature (15 K) in a wide-narrow-well InGaN/GaN light-emitting
diode with a narrow last well (1.5 nm) and a narrow next-to-last barrier (5 nm) is investigated to study the efficiency droop
phenomenon. A reduced droop in the wide wells and a reduced droop at low temperatures reveals that inferior hole transportation
ability induced Auger recombination is the root for the droop at high excitation levels. 相似文献
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Electroluminescence (EL) spectra of blue InGaN/GaN multiple-quantum-well light-emitting diode (LED) have been investigated over a wide range of injection current (0.001–200 mA) and at various temperatures (6–300 K). Surprisingly, with increasing the injection current the EL peak energy shows an initial blueshift accompanied by a broadening of the EL linewidth at low temperatures (below 30 K). This trend differs from the usual photoluminescence (PL) measurement results, which have shown that with increasing the optical excitation power the PL peak energy gave an initial blueshift accompanied by a narrowing of the PL linewidth at low temperatures. The anomalous current behavior of the EL spectra may be attributed to electron leakage results in the failure of Coulomb screening effect and the relative enhancement of the low-energetic localized state filling at low temperatures and low currents. The electron leakage for the LED is further confirmed by both the current dependence of the EL intensity and the temperature dependence of the EL efficiency. 相似文献
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精确的气体光谱参数对气体浓度、温度等的光谱精确反演测量具有十分重要的意义,针对当前主流光谱数据库(例如HITRAN)中数据与实际数值存在相当误差的问题,自主研制了一套基于静态冷却技术的低温光谱实验平台,用于精确测量低温下的气体吸收光谱参数.运用该低温光谱实验平台,采用可调谐二极管激光吸收光谱(TDLAS)技术测量了温度为230—340 K、压强为10—1000 Pa时7240—7246 cm~(-1)波段的纯水汽振转跃迁光谱.采用Voigt线型多峰拟合方法,获得了5条水汽振转跃迁谱在不同温度、不同压强下的积分吸光度值及洛伦兹展宽值,运用线性拟合的方法得到这5条吸收线的自展宽半峰全宽系数及参考温度下的线强值.运用不确定度传递公式,计算得到实验结果的不确定度,与HITRAN2012数据库中的线参数进行对比,所测的5条吸收线中实验结果与数据库值最大相差10.96%,且实验结果的不确定度为1.11%—2.98%(置信概率p=95%,包含因子k=2),小于HITRAN2012数据库值的不确定度. 相似文献
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The effect of the optical excitation signal intensity on the impulse response of a photodetector based on a set of metal-semiconductor-metal
(MSM) rectifier contacts is studied. The response of the detector is better at a low optical excitation signal. When the energy
of an optical excitation pulse is high, the response can be improved by increasing the bias voltage. The advantages of a GaN-based
MSM diode in detecting high- energy radiation pulses are established. It is shown that the speed of the GaN-based MSM detector
may reach 25 ps for a 60-pJ optical excitation pulse at a wavelength of 290 nm. 相似文献