RCE光电探测器顶部DBR的优化

对研制的VCSEL结构外延片制成的谐振腔增强型（简称RCE）光电探测器进行了物理分析和实验研究,由于VCSEL与RCE光电探测器对谐振腔反射镜的反射率要求不同,通过腐蚀VCSEL器件顶部DBR,改变顶镜反射率,能够得到量子效率峰值和半宽优化兼容的RCE光电探测器,实现VCSEL与RCE探测器的单片集成．     

平顶陡边响应的谐振腔增强型(RCE)光电探测器的分析

报道了一种具有平顶陡边响应的谐振腔增强型(RCE)光电探测器.使用数值模拟的方法对这种新型谐振腔增强型(RCE)光电探测器与传统的RCE光电探测器的响应曲线和串扰特性进行了分析和对比, 分析了在半导体材料生长时厚度偏差对平顶陡边响应的RCE光电探测器响应曲线的影响,还分析了入射光的入射角和偏振态对平顶陡边响应的RCE光电探测器响应曲线的影响.     

基于VCSEL的RCE探测器光电响应特性

对垂直腔面发射激光器（VCSEL）及由此制成的谐振增强型（RCE）光电探测器进行分析研究，激光器的Ith=3mA,ηd=15%,λp=839nm，和Δλ1／2=0．3nm，具有良好的波长选择特性，量子效率5％－35％（0V－5V），优化设计顶镜反射率，还能得到量子效率峰值和半宽优化兼容的VCSEL基RCE光电探测器。     

基于双吸收结构的谐振腔增强型光探测器

为了实现对传统谐振腔增强型（RCE）光探测器的优化,提出了一种具有双吸收结构的RCE光探测器。首先从理论上分析了它的量子效率和高速响应特性,然后将其与传统的RCE光探测器进行了比较。结果表明,双吸收结构RCE光探测器在保持高速响应特性的基础上,其量子效率较传统RCE光探测器得到了进一步提高。实验上成功制备了双吸收结构的...     

长波长、高灵敏度的InP／InGaAs谐振腔光电探测器

本文报道了一种能够实现高速、高灵敏度的InP基谐振腔增强型（RCE）光电探测器。它采用衬底入光方式，解决了在InP衬底上外延生长的InP/InGaAs介质膜分布布拉格反射镜（DBR）反射率低的问题，该探测器的吸收层厚度为0.2μm，在波长1.583μm处获得了80%的峰值量子效率，同时为了降低探测器的固有电容，利用质子注入技术使得器件的部分电极绝缘，实验结果表明质子注入不影响RCE光电探测器的量子效率。     

1064nm RCE探测器光电响应特性分析

对1064nm谐振腔增强型（RCE）光电探测器(PD)的光电响应特性进行了分析研究．利用MBE生长技术得到有源区分别为量子阱和量子点的1064nm RCE探测器的外延片,并对制作的探测器进行了各种光电特性测试．结果表明量子阱结构的RCE探测器量子效率峰值达到57%,谱线半宽6～7nm,峰值波长1059nm;而量子点结构的RCE探测器量子效率峰值达到30%,谱线半宽5nm,峰值波长1056nm．通过分析量子效率和吸收系数之间的关系,对两种结构器件的吸收进行了比较,发现虽然量子点探测器的吸收小,但通过合理设计共振腔等方法也可以达到较高的量子效率．两种结构的器件都有很好的Ｉ-Ｖ特性．     

1064nm RCE探测器光电响应特性分析

对1064nm谐振腔增强型(RCE)光电探测器(PD)的光电响应特性进行了分析研究.利用MBE生长技术得到有源区分别为量子阱和量子点的1064nm RCE探测器的外延片,并对制作的探测器进行了各种光电特性测试.结果表明量子阱结构的RCE探测器量子效率峰值达到57%,谱线半宽6～7nm,峰值波长1059nm;而量子点结构的RCE探测器量子效率峰值达到30%,谱线半宽5nm,峰值波长1056nm.通过分析量子效率和吸收系数之间的关系,对两种结构器件的吸收进行了比较,发现虽然量子点探测器的吸收小,但通过合理设计共振腔等方法也可以达到较高的量子效率.两种结构的器件都有很好的I-V特性.     

GaAs基量子阱谐振腔增强型光电探测器特性研究

通过对谐振腔增强型(RCE)光电探测器的理论分析和实验测试结果,证明对应不同光束入射角度,RCE光电探测器的模式波长按一定规律可调谐.并给出当入射角度变化10°～60°,模式调谐范围约为40nm,而谐振波长处的量子效率峰值及半高宽FWHM的变化与材料吸收系数紧密相关.     

GaAs基量子阱谐振腔增强型光电探测器特性研究

通过对谐振腔增强型(RCE)光电探测器的理论分析和实验测试结果,证明对应不同光束入射角度,RCE光电探测器的模式波长按一定规律可调谐.并给出当入射角度变化10°～60°,模式调谐范围约为40nm,而谐振波长处的量子效率峰值及半高宽FWHM的变化与材料吸收系数紧密相关.     

一种具有亚波长光栅结构的光探测器的设计

高速智能光纤通信系统和网络的飞速发展对光电探测器提出了更高要求.利用严格耦合波(RCWA)理论,给出了在亚波长光栅(SWG)下方具有分布布拉格反射镜(DBR)结构的理论分析模型,将这种结构作为反射镜应用于谐振腔增强型光探测器(RCE PD)的设计中.仿真表明由于SWG的引入,只需要4对λ/4厚度的InGaAsP/InP系DBR,可使整体膜系结构实现在中心波长1.55 μm处反射率达到99.7%,在1.40 μm至1.62/μm范围内反射率高于99%.引入SWG后的RCE PD在1.55 μm附近的量子效率接近90%,串扰衰减系数与量子效率的乘积超过15 dB.有效地解决了InGaAsP/InP介质膜系DBR作为谐振腔反射镜反射率低、反射带宽窄的问题.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

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