在（311）面上所生长的Al_xGa_（1－x）As／GaAs单量子阱特性

文章报道了用分子束外延（ＭＢＥ）法在６００℃和６５０℃下，在Ｓｉ掺杂的ＧａＡｓ衬底的（３１１）Ａ和（３１１）Ｂ面上成功地生长了高质量的ＡｌｘＧａ１－Ａｓ／ＧａＡｓ单量子阱材料。计算了光荧光（ＰＬ）峰值能量，并与实验作了比较。讨论了（３１１）Ａ和（３１１）Ｂ面上的不同生长特性。     

Anomalous capacitance of quantum well double-barrier diodes

The S-parameters of several different quantum well double barrier diodes have been measured. A technique has been developed for measuring whisker contacted diodes with and HP 8510B automatic network analyzer. Special coaxial mounts using K-connectors were designed to enable measurements up to 20 GHz. The voltage-dependent conductance and capacitance were derived from the measured reflection coefficient of each device. The C/V characteristics were observed to exhibit an anomalous increase at voltages corresponding the the negative differential resistance region (NDR). These are the first reported S-parameter measurements in the negative differential resistance region of quantum well double barrier diodes. A theory is presented that explains, in part, the observed results.     

10W QCW operation of a proton implanted GaAlAs diode laser array

We report one thick layer of hard-baked photoresist mask.The laser array stripe pattern was defined by standard wet lithography.With this mask, a 10 W QCW(quasi-continuous wave) operation of a narrow proton implanted multiple stripe conventional single quantum well separate confinement heterostructure(SQW-SCH) GaAlAs diode laser array has been realized.These devices exhibit the lateral far-field radiation pattern of a phase-locked array of gain-guided semiconductor injection laser array. The twenty stripe laser array has a lateral far-field beam divergence full width at half maximum (FWHM) of less than 3°, and three twenty stripe laser array has a beam divergence in the plane of the junction of about 9°.     

Numerical study of a well boat operating at a fish farm in current

Dynamic response of a well boat operating at a fish farm in current is investigated numerically. An objective is to determine the operational conditions of the well boat. In terms of the fish farm, a realistic set-up (with single cage) is considered, including a floating collar, an elastic sinker tube, a flexible-closed net cage and a complex mooring system. A time-domain solution is used to find the steady configuration and response. Transverse viscous current loads are estimated using the cross-flow principle. The drag coefficients are obtained empirically by considering cross-sectional details, free surface and three-dimensional (3D) flow effects. The drag force is experimentally validated. The effect of the ship wake on the net loading is also assessed.The most critical scenario with the well boat placed at the weather side of the fish farm is analyzed in detail. Critical response variables for operational limits are the maximum anchor-line tensions and floater stresses. Numerical results show that the anchor loads will increase more than 40% in small current velocities and up to 90% in high current velocities due to the viscous current loads on the boat. There is also a strong increase of the floating collar deformations and stresses when the well boat is in contact with the floating collar.A sensitivity analysis has been carried out to identify the physical parameters affecting the anchor loads and the maximum stress in the floating collar. From our studies, the anchor loads are more sensitive to current direction, bottom weight system, sinker tube depth and mooring line properties (pretension load, anchor chain weight, etc.) and less sensitive to other parameters such as floating collar stiffness and cross-sectional drag coefficients of the well boat. The shading effect of the well boat on the fish-farm inflow has been examined and appeared not negligible with 4% to 10% reduction of the anchor loads for the studied current conditions. The maximum stress in the floating collar is sensitive to well-boat loads related parameters (current direction, cross-sectional drag coefficient) and pretension load in the anchor line; not so sensitive to net loading related parameters such as sinker tube depth and sinker tube weight.Lastly, the operational conditions of the well boat at the fish farm were discussed. Numerical results show that the maximum stresses in the floating collar should be of major concern. The loads in the mooring lines are moderate compared with the corresponding breaking limits.     

GaAs/AlGaAs多量子阱FET-SEED灵巧象元

将GaAs／AlGaAs多量子阱光探测器、光调制器与GaAs场效应晶体管（FET）混合集成,构成FET-SEED灵巧象元。光探测器和光调制器均为反射型自电光效应器件（SEED）,光源为骨子阱半导体激光器。测出的光输出Pout／光输入Pin特性表明,光输入信号对光输出信号有明显的调制作用,光输入信号较小的变化可以导致光输出信号较大的变化。     

能带混合量子阱的触发功能和异质谷间转移电子放大器件的研究

运用MonteCarlo理论模拟、二极管除穿伏安特性、器件振荡性能和射频输入信号激励下的放大功能研究了异质谷间转移电子器件中能带混合量子阱的触发功能。理论和实验研究发现，当能带混合量子讲中没有产生足够的异质谷间转移电子效应时，即使有源层中加有足够的电场仍然不能产生振荡。异质谷间转移电子效应成为器件进行射频工作的必要条件。在适当设计的器件中，运用输入射频信号也能激励异质谷间转移电子效应而触发输出放大信号。应用这一原理研制成8mm波段工作的稳态放大器，解决了二极管稳态放大器中的自激振荡问题。最后讨论了利用能带混合量子讲的触发功能来制作新的三端器件和各类功能器件的可能性。     

GaAs／AIGaAs量子阱红外探测器的发展

半导体超晶格量子阱红外探测器的研制近年来取得了引人注目的成果,其中 GaAs/AlGaAs 红外器件的发展最快。本文在简要综述其单元探测器的基础上,着重介绍这种材料用于红外探测器列阵和焦平面的新成果。     

快速热退火提高应变InAs／InP量子阱结构的晶体质量

研究了快速热退火对应变ＩｎＡｓ／ＩｎＰ单晶子阱结构光学性质的影响。样品经最佳条件７００℃，５ｓ的快速热退火，８Ｋ温度下量子阱的荧光强度地加了４倍，量子阱荧光峰仅蓝移１．５ｍｅＶ。     

Well Oriented ZnO Nanorods Array: Negative Resistance and Optical Switching

Well‐oriented ZnO nanorods (NRs) arrays were grown on Si, alumina, quartz, and FTO substrates through a ZnO seed layer followed by low temperature wet chemical process. The influence of sputtered ZnO seed layer thickness (100, 50, 32, and 16 nm), annealing temperature and CuO_x coverage on the characteristics of ZnO NRs were investigated in this study. The crystalline structural, chemical, morphological, optical, and electrical properties of ZnO NRs arrays were studied by X‐ray diffraction (XRD), field emission‐ scanning electron microscopy equipped by energy dispersive X‐ray spectroscopy (FE‐SEM/EDX), Raman scattering, UV/Vis ‐ near IR absorption spectroscopy and current‐voltage characteristic. XRD and Raman spectra measurement revealed that the synthesize ZnO displayed hexagonal wurtzite structure. The individual rod diameter, density, and orientation can be controlled by varying the seed layer thickness. The mean diameter and maximum length of ZnO NRs are around 55–66 nm and 282 nm, respectively. ZnO NRs/ ZnO thin film structure shows optical switching and negative differential resistance behavior as applicable to ON/OFF gate and memory devices.     

A facile and versatile protocol for the one-pot PhI(OAc)2 mediated divergent synthesis of quinazolines from 2-aminobenzylamine

In this present work iodobenzenediacetate (PIDA) has been found to be the key reagent in absence or presence of catalytic amount of molecular iodine (I₂)/zinc chloride (ZnCl₂) to construct quinazoline scaffold from 2-aminobenzylamine and a variety of easily available aldehydes, aryl and aliphatic amines, aliphatic and aryl alcohols and nitriles. This protocol provides mild and robust conditions along with great versatility to synthesize 2-substituted quinazolines from diverse starting materials in good to excellent yields. The developed protocol is also well applicable to reactants containing ease to oxidation prone functional groups.