Preferential orientation growth of AIN thin films on Si (111) substrates by LP-MOCVD

Aluminum nitride (AIN) thin films were deposited on Si (111) substrates by low pressure metalorganic chemical vapor deposition system. The effects of the V/III ratios on the film structure and surface morphology were systematically studied. The chemical states and vibration modes of AIN films were characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer. The optical absorption property of the AIN films, characterized by ultraviolet-visible-near infrared spectrophotometer, exhibited a sharp absorption near the wavelength of 206 mm. The AIN (002) preferential orientation growth was obtained at the V/III ratio of 10,000 and the preferential growth mechanism is presented in this paper according to the thermodynamics and kinetics process of the AIN growth.

Growth of heavily Zn-doped InGaAs at low temperature by LP-MOCVD

Epitaxial growth of Zn-doped InGaAs on InP substrates has been carried out at 550degreesC by LP-MOCVD. Hole concentration as high as 6 x 10(19)cm(-3) has been achieved at the H-2 flow rate of 20 sccm through DEZn bubbler. The lattice constant of Zn-doped InGaAs was found to be dependent on the flow rate of DEZn, and the tensile strain mismatch increases with increasing H-2 flow rate of DEZn. The negative lattice mismatch of heavily Zn-dopped InGaAs may be due to, the small covalent bonding radius of zinc and the combination of butane from ethyl of DEZn,and TEGa. And the latter accelerates the pyrolysis of TEGa, which is the dominant mechanism in determining the negative mismatch of Zn-doped InGaAs. (C) 2003 Elsevier B.V. All rights reserved.

Effects of V/III ratio on InGaAs and InP grown at low temperature by LP-MOCVD

Effects of V/III ratio on heavily Si doped InGaAs and InP were studied using low pressure metalorganic chemical vapor deposition (LP-MOCVD) at a growth temperature of 550degreesC. In InGaAs, as the V/III ratio decreases from 256 to 64, the carrier concentration increases from 3.0 x 10(18) to 5.8 x 10(18) cm(-3), and the lattice mismatch of InGaAs to InP was observed to vary from -5.70 x10(-4) to 1.49 x 10(-3). In InP, when the V/III ratio decreases from 230 to 92, the same trend as that in Si doped InGaAs was observed that the carrier concentration increases from 9.2 x 10(18) to 1.3 x 10(19) cm(-3). The change of AsH3 was found to have stronger effect on Si incorporation in InGaAs at lower growth temperature than at higher growth temperature. (C) 2003 Elsevier B.V. All rights reserved.

Manifold covering theory in biomimetic pattern recognition

We describe a new model which is based on the concept of cognizing theory. The method identifies subsets of the data which are embedded in arbitrary oriented lower dimensional space. We definite manifold covering in biomimetic pattern recognition, and study its property. Furthermore, we propose this manifold covering algorithm based on Biomimetic Pattern Recognition. At last, the experimental results for face recognition demonstrates that the correct rejection rate of the test samples excluded in the classes of training samples is very high and effective.

多量子阱电吸收调制DFB激光器的一种新型LP-MOCVD对接生长方法

提出了一种提高多量子阱电吸收调制DFB-LD集成器件（EML）耦合效率的对接生长方法。采用LP-MOCVD外延方法，制作了对接方法不同的三种样片，通过扫描电镜研究它们的表面及对接界面形貌，发现新对接结构的样片具有更好的对接界面。制作出相应的三种EML管芯，从测量所得到的出光功率特性曲线，计算出不同对接方法下EML管芯的耦合效率和外量子效率。实验结果表明，这种对接生长方案，可以获得光滑的对界面，显著提高了激光器和调制器之间的耦合效率（从常规的17%提高到78％）及EML器件的外量子效率（从0.03mW/mA提高到0.15mW/mA)。

生长温度对长波长InP/AlGaInAs/InP材料LP-MOCVD生长的影响

研究不同生长温度下的InP/AlGaInAs/InP材料LP-MOCVD生长，用光致发光和X射线双晶衍射等测试手段分析了其材料特性，得到了室温脉冲激射1.3μm AlGaInAs有源区SCH-MQW结构材料，为器件制作研究打下了基础。

Multi-Wavelength InGaAsP Lasers Grown by LP-MOCVD Selective Area Growth

国家863计划

1.3μm低阈值InGaAsP/InP应变补偿MQW激光器的LP-MOCVD生长

报道了用低压金属有机物化学气相淀积(LP-MOCVD)方法外延生长InGaAsP/InP应变补偿多量子阱结构。用此材料制备的掩埋异质结(BH)条形结构多量子阱激光器具有极低阈值电流4～6mA。20～40℃时特征温度T_0高达67K，室温下外量子效率为0.3mW/mA。

低阈值1.3μm InGaAsP/InP应变补偿多量子阱DFB激光器LP-MOCVD生长

报道了用低压－金属有机化学气相淀积(LP-MOCVD)方法制作1.3μm应变补偿多量子阱结构材料。X射线双晶衍射摇摆曲线可清晰地看到±4级卫星峰和卫星峰间的Pendellosong条纹。整个有源区的平均应变量几乎为零。用掩埋异质结(BH)条形工艺制备的含一级光栅的DFB激光器室温下阈值电流2～4mA,外量子效率0.33mW/mA,线性输出光功率达30mW,边模抑制比(SMSR)大于35dB。20～40℃下的特征温度T_0为67K。

LP-MOCVD制备AlGaInP高亮度橙横色发光二极管

利用LP-MOCVD外延生长AlGaInP DH 结构橙黄色发光二极管。引入厚层Al_(0.7)Ga_(0.3)As电流扩展层和Al_(0.5)Ga_(0.5)As-AlAs分布布拉格反射器(KBR)。20mA工作条件下，工作电压1.9V,发光波长峰值在605nm,峰值半宽为18.3nm,管芯平均亮度达到20mcd,最大29.4mcd,透明封装成视角(2θ_(1/2)15°的LED灯亮度达到1cd。

LP-MOVPE生长的低阈值1.3μm InGaAsP/InP 压、张应变交替 MQW 激光器特性

国内首次报道了LP-MOVPE法生长高质量的高、张应变交替InGaAsP多量子阱结构的研制过程及其材料的高精度X-ray双晶摇摆衍射曲线和荧光光谱特性表征。经过双腔面镀增透射膜后，其TE模与TM模自发发射谱光强差为3dBm，呈现偏振补偿特性。

LP-MOVPE生长的1.3μmInGaAsP/InP张压应变交替MQW特性

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