共查询到19条相似文献,搜索用时 133 毫秒
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利用扫描电子显微镜(SEM)研究了在选择外延MOVPE生长InGaAsP材料中,厚度增强因子随SiO2掩模宽度的变化,生长条件(如生长压力、Ⅲ族源流量等)对厚度增强因子的影响.随着生长压力的增加,生长速率下降,选择性增强;随着In源流量的增加,生长速率上升,选择性下降.制备了最大厚度增强因子达3.4的InGaAsP体材料.通过扫描电镜观察,得到了较平坦的生长界面和表面形貌.为用选择生长法制备DFB激光器与模斑转换器集成器件提供有效的方法.(OH12) 相似文献
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用 x 射线双晶衍射仪研究了(001),InP 衬底上生长的 InGaPAs外延层在垂直及平行于异质界面方向上的晶格失配。观察到在(001)生长方向上晶格常数随四元外延层厚度变化,而横向上却没有晶格失配。发现四元外延层 x 射线回摆曲线大的半值宽度归因于沿厚度方向晶格常数的变化。 相似文献
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采用Ga/AsCl_3/H_2体系,用SnCl_4作掺杂剂,已生长了用于双栅FET的n~+-n-n~-多层外延材料.在一次外延生长中连续生长的n~+-n-n~-多层外延材料的外延层厚度和载流子浓度的均匀性良好.用该材料制作的双栅FET的微波特性也有明显改善.在2GHz和8GHz下,NF分别为0.9dB和2.8dB,相关增益G_a分别为15.5dB和18dB. 相似文献
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GAO Hua-li WU Chong-qing LI Ya-jie NI Dong 《光电子快报》2006,2(2):142-144
Semiconductoropticalamplifiers(SOA)arewidely usedincommunicationsystembecauseoftheirsmall volumeandlowpowerconsumption.Theycanbeusedasboosters,on lineamplifiers,andpreamplifier.Asnon linearcomponents,theycanalsobeusedinoptical switch,multiplexers/demultip… 相似文献
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Zah C.E. Bhat R. Menocal S.G. Favire F. Lin P.S.D. Gozdz A.S. Andreadakis N.C. Pathak B. Koza M.A. Lee T.P. 《Electronics letters》1991,27(18):1628-1630
1.5 mu m compressive-strained multiquantum-well distributed-feedback lasers have been fabricated and characterised. 5.5 mA threshold current, 1 MHz mW linewidth-power product, and 600 kHz minimum linewidth were measured on 500 mu m long devices. Measured threshold current as low as 2.2 mA was also obtained on 150 mu m long devices. Both low threshold and narrow linewidth are attributed to the reduced transparency current and linewidth enhancement factor due to the effect of strain.<> 相似文献
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制备了基于CuPc…C60混合层异质结有机光伏器件,将其与CuPc-C60双层结构光伏器件进行对比研究。结果表明混合层结构器件性能得到改善,其开路电压、短路电流密度、填充因子和光电转换效率都有提高,分别从CuPc-C60双层结构器件的0.39V、1.92mA/cm2、0.36%、0.48依次提高到CuPc…C60混合层结构器件的0.48V、2.21mA/cm2、0.54%、0.51。根据整数电荷转移模型来分析光伏器件D/A界面及有机材料-ITO衬底界面特性,认为混合层异质结有机光伏器件给体材料HOMO与受体材料LUMO的能级差增加使得器件开路电压提高。混合层异质结有机光伏器件D/A界面面积增加和给体材料HOMO与受体材料LUMO的能级差增加都提高了激子的分离效率,所以器件的短路电流密度增加。 相似文献
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An efficient organic photovoltaic (OPV) cell with an indium-tin-oxide/CuPc/C60/Ag structure has been investigated by changing the film thickness of organic layers. A high olin-circuit voltage (Yoc) of 0.5 V, a short-circuit current density (Jsc) of 5.81 mA/cm^2, and a high power conversion efficiency (ηp) of 1.2% were achieved at an optimum film thickness. The results demonstrate that material thickness is an important factor to cell optimization, especially for maximizing the absorption rate as will as reducing the cell resistance. Experimental results also indicate that the power conversion efficiency increases from 1.2% to 1.54% as a BCP exciton blocking layer of 10 nm is introduced. 相似文献
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Thijs P.J.A. van Dongen T. Tiemeijer L.F. Binsma J.J.M. 《Lightwave Technology, Journal of》1994,12(1):28-37
Compressively and tensile strained InGaAsP-InP MQW Fabry-Perot and distributed feedback lasers emitting at 1.3-μm wavelength are reported. For both signs of the strain, improved device performance over bulk InGaAsP and lattice-matched InGaAsP-InP MQW lasers was observed. Tensile strained MQW lasers show TM polarized emission, and with one facet high reflectivity (HR) coated the threshold currents are 6.4 and 12 mA at 20 and 60°C, respectively. At 100°C, over 20-mW output power is obtained from 250-μm-cavity length lasers, and HR-coated lasers show minimum thresholds as low as 6.8 mA. Compressively strained InGaAsP-InP MQW lasers show improved differential efficiencies, CW threshold currents as low as 1.3 and 2.5 mA for HR-coated single- and multiple quantum well active layers, respectively, and record CW output powers as high as 380 mW for HR-AR coated devices. For both signs of the strain, strain-compensation applied by oppositely strained barrier and separate confinement layers, results in higher intensity, narrower-linewidth photoluminescence emissions, and reduced threshold currents. Furthermore, the strain compensation is shown to be effective for improving the reliability of strained MQW structures with the quantum wells grown near the critical thickness. Linewidth enhancement factors as low as 2 at the lasing wavelength were measured for both types of strain. Distributed feedback lasers employing either compressively or tensile strained InGaAsP-InP MQW active layers both emit single-mode output powers of over 80 mW and show narrow linewidths of 500 kHz 相似文献
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Osinski J.S. Grodzinski P. Zou Y. Dapkus P.D. Karim Z. Tanguay A.R. Jr. 《Photonics Technology Letters, IEEE》1992,4(12):1313-1315
Buried heterostructure lasers operating at a wavelength of 1.5 μm with four compressively strained quaternary quantum wells (strain ~1.8%, thickness ~90 Å) and current blocking layers were made using atmospheric pressure metalorganic chemical vapor deposition. Pulsed room-temperature threshold currents for uncoated devices as low as 4.1 mA and as low as 0.8 mA for devices with high reflectivity mirror coatings are reported. The dependence of threshold current on active region width is consistent with broad-area laser measurements 相似文献
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Jiu‐Ju Feng Ulrich Gernert Peter Hildebrandt Inez M. Weidinger 《Advanced functional materials》2010,20(12):1954-1961
A novel Ag–silica–Au hybrid device is developed that displays a long‐range plasmon transfer of Ag to Au leading to enhanced Raman scattering of molecules largely separated from the optically excited Ag surface. A nanoscopically rough Ag surface is coated by a silica spacer of variable thickness from ~1 to 21 nm and a thin Au film of ~25 nm thickness. The outer Au surface is further functionalized by a self‐assembled monolayer (SAM) for electrostatic binding of the heme protein cytochrome c (Cyt c) that serves as a Raman probe and model enzyme. High‐quality surface‐enhanced resonance Raman (SERR) spectra are obtained with 413 nm excitation, demonstrating that the enhancement results exclusively from excitation of Ag surface plasmons. The enhancement factor is estimated to be 2 × 104–8 × 103 for a separation of Cyt c from the Ag surface by 28–47 nm, corresponding to an attenuation of the enhancement by a factor of only 2–6 compared to Cyt c adsorbed directly on a SAM‐coated Ag electrode. Upon immobilization of Cyt c on the functionalized Ag–silica–Au device, the native structure and redox properties are preserved as demonstrated by time‐ and potential‐dependent SERR spectroscopy. 相似文献