共查询到19条相似文献,搜索用时 118 毫秒
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文中理论研究了InP/In0.53Ga0.47As/InP异质结透射式红外光电阴极的时间响应特性,光谱响应范围1.0~1.7 m。在场助偏压的作用下,模拟计算了光激发的电子在阴极内部的传输特性。模拟计算表明,光电阴极的响应速度随场助偏压的增大而加快;随光吸收层厚度的增大而减慢;随光吸收层掺杂浓度的增大,光电阴极的响应速度变慢。发射层厚度及掺杂浓度的增大都会使得阴极的响应时间加长。经过对阴极结构参数和掺杂浓度的优化,得到在吸收层和发射层厚度分别为2 m、0.5 m,掺杂浓度分别为1.51015 cm-3、1.01016 cm-3时,在适当场助偏压下光电阴极的响应时间可优于100 ps。 相似文献
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为了探索发射层厚度对指数掺杂Ga1-xAlxAs/GaAs光电阴极光学性能与光电发射性能的影响,实验制备了两种发射层厚度不同的阴极样品,并测试得到400~1000 nm内反射率、透射率与光谱响应曲线。实验结果说明发射层2.0 μm厚的样品比1.6 μm厚的样品性能更好。利用薄膜光学矩阵理论公式计算阴极膜系反射率、透射率、吸收率与发射层厚度的关系公式,并对原有的量子效率公式进行光谱反射率和短波截止限的修正。用修正后的公式仿真不同发射层厚度下光阴极吸收率与光谱响应曲线,指出发射层厚度对阴极光学性能与光电发射性能的不同影响。进一步计算得到指数掺杂的Ga1-xAlxAs/GaAs光电阴极最佳发射层厚度范围是1.8~2.4 μm。 相似文献
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为了探索发射层厚度对指数掺杂Ga1-χAlχAs/GaAs光电阴极光学性能与光电发射性能的影响,实验制备了两种发射层厚度不同的阴极样品,并测试得到400μm~1 000 nm内反射率、透射率与光谱响应曲线.实验结果说明发射层2.0 μm厚的样品比1.6μm厚的样品性能更好.利用薄膜光学矩阵理论公式计算阴极膜系反射率、透射率、吸收率与发射层厚度的关系公式,并对原有的量子效率公式进行光谱反射率和短波截止限的修正.用修正后的公式仿真不同发射层厚度下光阴极吸收率与光谱响应曲线,指出发射层厚度对阴极光学性能与光电发射性能的不同影响.进一步计算得到指数掺杂的Ga1-χAlχAs/GaAs光电阴极最佳发射层厚度范围是1.8μm~2.4μm. 相似文献
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通过计算电子到达阴极面时的能量分布和求解电子隧穿表面势垒的薛定谔方程得到了透射式NEA GaAs光阴极发射电子能量分布的计算公式.利用该公式仿真研究了阴极表面势垒形状对电子能量分布的影响,发现I势垒变化对阴极的量子效率影响显著,其中尤以I势垒宽度影响更大,而Ⅱ势垒则影响阴极的能量展宽,其中真空能级的升高可使阴极电子能量分布更集中,但却牺牲了一定的阴极量子效率.拟合分析了实验测试的透射式阴极电子能量分布曲线,实验与理论曲线吻合得很好,并得到了阴极的表面势垒参数. 相似文献
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大屏幕场助热电子发射平板显示 总被引:6,自引:1,他引:5
有源矩阵驱动的平面场发射阴极是大屏幕显示的主要候选部件。阴极结构、材料组分以及结晶状态强烈地影响电子发射。选择具有低功函数的上电极材料 ,并且引入界面态控制层将能够降低驱动电压和提高电子发射率。 相似文献
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通过对透射式GaAs光阴极“三物理过程”的描述和理论分析,指出了影响量子效率的不利因素,讨论和提出了克服,消除这些不利因素的方法,措施和途径。 相似文献
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研究了变掺杂浓度结构对GaAs负电子亲和势光电阴极积分光电灵敏度的影响.通过MBE生长了两组GaAs同质外延样品.其中一组采用了均匀掺杂的单层结构,Be掺杂浓度为1×1019cm-3;另一组采用了变掺杂的多层结构,从衬底开始Be的掺杂浓度依次为1×1019,7×1018,4×1018和1×1018cm-3.负电子亲和势光电阴极通过在高真空系统中交替通入Cs和O激活得到.在线光谱响应测试曲线表明,多层Be掺杂结构光阴极的积分光电灵敏度比单层Be掺杂结构光阴极的积分光电灵敏度至少提高了50%.两种结构的GaAs样品表现出不同的表面应力情况. 相似文献
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研究了光照强度和残余气体对阴极稳定性的影响,比较阴极在管壳内和激活室内的阴极稳定性,用俄歇谱仪分析激活的GaAs光电阴极表面和灵敏度衰减到O时的GaAs光电阴极表面。结果表明,真空中有害残余气体与阴极表面的相互作用是引起阴极衰减的主要原因。 相似文献
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We designed two transmission-mode GaAs/AlGaAs photocathodes with different AlxGa1-xAs layers, one has an AlxGa1-xAs layer with the Al component ranging from 0.9 to 0, and the other has a fixed Al component 0.7. Using the first-principle method, we calculated the electronic structure and absorption spectrum of AlxGa1-xAs at x=0, 0.25, 0.5, 0.75 and 1, calculation results suggest that with the increase of the Al component, the band gap of AlxGa1-xAs increases. Then we activated the two samples, and obtained the spectral response curves and quantum efficiency curves; it is found that sample 1 has a better shortwave response and higher quantum efficiency at short wavelengths. Combined with the band structure diagram of the transmission-mode GaAs/AlGaAs photocathode and the fitted performance parameters, we analyze the phenomenon. It is found that the transmission-mode GaAs/AlGaAs photocathode with variable Al component and various doping structure can form a two-stage built-in electric field, which improves the probability of shortwave response photoelectrons escaping to the vacuum. In conclusion, such a structure reduces the influence of back-interface recombination, improves the shortwave response of the transmission-mode photocathode. 相似文献
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谈凯声 《电子科学学刊(英文版)》1988,5(1):53-56
A stable surface layer is essential for a high stable long life-span photocathode.Byusing fluorine instead of oxygen in activating the surface of GaAs suhstrate,the strongelectronegativity of fluorine may improve the stability of photocathode.Life-span of reflectiveGaAs(Cs,F)photocathode has been made up to 8,500 hours.Furthermore,Its technologicalreproducibility and anti-contamination ability are better than those of GaAs(Cs,O_2)photocathodes. 相似文献
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《Electron Devices, IEEE Transactions on》1974,21(10):641-649
Several types of transmission-mode negative electron affinity (NEA) photocathodes were investigated. The first group consisted of GaAs cathodes of various thicknesses grown on a composite structure composed of a GaP substrate and a Ga(As,P) buffer layer. These cathodes were of two types, one having an abrupt Ga(As,P)/GaAs interface and the other having a compositionally graded interface. The latter type exhibited the highest transmission-mode quantum efficiency, 0.11 electron per incident photon at 0.85 μm. It is assumed that the electron diffusion length L in the GaAs layer is limited by misfit dislocations arising from the lattice mismatch between the GaAs and the Ga(As,P) buffer layer. L increased with cathode layer thickness more rapidly for the graded structure, suggesting that misfit dislocation propagation into the GaAs layer is less when the dislocations are generated gradually (graded structure) than when they are introduced abruptly (ungraded structure). The second group of samples consisted of (In, Ga)As alloy cathodes of various compositions grown on both GaAs and GaP substrates with lattice-mismatch-reducing buffer layers of (In, Ga)As, (In, Ga)P, and Ga(As,P). It was found that photosensitivity was improved significantly by reducing the amount of lattice mismatch between the (In, Ga)As cathode layer and the substrate or buffer layer. Using an (In, Ga)As cathode with an (In,Ga)P buffer layer grown on a GaP substrate, transmission quantum efficiencies in excess of 0.01 were obtained over the relatively broad wavelength range of 0.7 to 1.04 µm. 相似文献
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采用溶液生成法制备了有机铅卤化钙钛矿(CH3 NH3PbI3)晶体粉末,并以过量的PbI2对其进行掺杂,采用X射线衍射谱(XRD)技术研究了掺杂前后样品的晶体结构变化.表面光电压谱(SPS)和相位谱(PS)显示掺杂前后的CH3 NH3 PbI3均为p型半导体,但后者有更强的光伏响应.场诱导表面光电压谱(FISPS)表明:当加正电场时,掺杂前后的CH3NH3PbI3均表现为p型半导体的载流子特性,当加负偏压时掺杂后的CH3NH3PbI3易形成反型层,出现光伏反转,且外加负偏压越大,光伏反转区域越大,表现出双极导电特性. 相似文献
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R. Srnanek G. Irmer J. Osvald A. Christoffi D. Radziewicz 《Microelectronics Journal》2008,39(12):1439-1443
Micro-Raman spectroscopy was used to characterize beveled Zn delta (δ)-doped GaAs structures. By adapting procedures previously developed for the study of Si δ-doped GaAs structures, Zn-doping profiles were obtained for a set of structures prepared with different doping levels. Values of the doping spike concentration and the full-width at half-maximum of the doping profile were compared with the values obtained by the electrochemical capacitance-voltage (EC-V) and secondary ion mass spectroscopy (SIMS) methods. The good correspondence between this Raman procedure and other well-known methods proves the validity of the technique for determining doping profiles in Zn δ-doped GaAs structures. 相似文献