808nm大功率无铝有源区非对称波导结构激光器

采用分别限制非对称波导结构,将光场从对称分布变为非对称分布,降低了载流子光吸收损耗,并允许p型区具有更高的掺杂水平,从而使器件电阻降低。对GaAsP/GaInP张应变单量子阱（SQW）非对称波导结构激光器的光场特性进行了理论分析,设计了波导层厚度,并制作了波长为808 nm的无铝有源区大功率半导体激光器.器件综合特性测试结果为

CMOS超高频整流器

提出了一个适用于无源UHF RFID标签芯片的全CMOS整流器.整流器包括射频-直流转换电路、偏置电路、直流-直流转换电路和振荡器电路.整流器的工作频率范围是860～960 MHz.基于0.18μm,1p6m的标准数字CMOS工艺,设计并实现了无源UHF RFID标签芯片的整流器.该设计采用开关电容电路技术动态地消除了CMOS管开启电压的问题,在标准数字CMOS工艺下实现了高效率的超高频整流器.整流器的面积为180μm×140μm.当输入900MHz,-16dBm的射频信号时,整流器的输出电压为1.2V,启动时间为980μs.

光子晶体的微腔特性

为了设计一种高品质因子的光子晶体微腔和研究单缺陷光子晶体微腔谐振模波长随晶格常数的变化规律,使用时域有限差分法（difference time-domain method）和基于Baker算法的Padé近似方法计算了半导体材料上空气孔阵列光子晶体微腔的谐振模波长和品质因子.得到的新型光子晶体微腔的品质因子达246510,单缺陷光子晶体微腔模波长随晶格常数α和孔半径r的近似为线性变化关系

980nm单模运转未镀增透膜光纤光栅激光器

提出了一种工艺简单的980 nm未镀增透膜的光纤光棚外腔半导体激光器.首先从理论上分析了边模抑制比(SMSR)与激光二极管前表面反射率R2、外腔长Lext和激光二极管-光纤耦合效率之间的关系,得出边模抑制比随R2和Lext的增大而减小,而随着激光二极管-光纤的耦合效率的提高而增大.从计算结果中还可以看出,即使半导体激光器不镀增透膜(R2=0.3时),在其它参量合适的情况下,边模抑制比仍可大于40 dB.然后,对其进行实验验证,在半导体激光器未镀模的情况下,选择光纤光栅发射率为0.5,外腔长为12.5 cm,输入电流为28.8 mA(约为阈值电流的2.4倍)时,通过仔细调节恒温、恒流电路,实现了边模抑制比高于40 dB的稳定的单纵模输出,外腔激光器的线宽优于1.6 MHz.

倒装焊组装的光电混合集成RCE探测器面阵

报道了一种可用于并行光传输系统的64 * 64光探测器面阵。器件结构采用谐振腔增强型（RCE），吸收区由3层InGaAs/GaAs量子阱构成，谐振腔是由2组多层布拉格反射镜组成，工作波长位于980 nm。该器件利用倒装焊技术，将GaAs基的谐振腔增强型光探测器面阵与相应的Si基标准CMOS集成电路混合集成在一起，形成具备64 * 64路光并行接收及处理的大规模光电集成探测器面阵器件，并对光探测器面阵的主要特性进行了测试，测试结构显示该面阵具有均匀的电特性，反向偏压均大于14 V，暗电流约为10 nA数量级。

磁性多层膜中SiO_2/Ta界面反应及其对缓冲层的影响

磁性多层膜常以金属Ta作为缓冲层。利用磁控溅射方法在表面有300nm厚SiO_2氧化膜的单晶硅(100)基片上沉积了Ta/NiFe/Ta薄膜。采用X射线光电子能谱（XPS）对该薄膜进行了深度剖析，并且对获得的Ta 4f和Si 2p的高分辨XPS谱进行计算机谱图拟合分析。结果表明在SiO_2/Ta界面处发生了化学反应

MOCVD生长碳掺杂GaAs/AlGaAs大功率半导体激光器

利用低压金属有机金属化合物汽相淀积方法,以液态CCl_4为掺杂源生长了高质量C掺杂GaAs/AlGaAs材料,并对生长机理、材料特性以及C掺杂对大功率半导体激光器的影响进行了分析。在材料研究的基础上生长了以C为P型掺杂剂的GaAs/AlGaAs/InGaAs应变量子阱半导体激光器结构,置备了高性能980 nm大功率半导体激光器。

Structural properties of polycrystalline silicon films formed by pulsed rapid thermal processing

A novel pulsed rapid thermal processing (PRTP) method has been used for realizing the solid-phase crystallization of amorphous silicon films prepared by PECVD. The microstructure and surface morphology of the crystallized films are investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). The results indicate that this PRTP is a suitable post-crystallization technique for fabricating large-area polycrystalline silicon films with good structural qualities such as large grain size, small lattice microstain and smooth surface morphology on low-cost substrate.

Luminosity determination for the dd→αK+K-experiment atANKE/COSY

High resolution studies of a0/f0(980) decays into channels involving open strangeness are currently being performed at COSY-Jülich. As a “filter” for isospin-zero intermediate states, i.e. to selectively produce the f0(980) resonance, the dd→αK+K− reaction was measured with the magnetic ANKE spectrometer. In order to determine the luminosity of this experiment, the elastically and quasi-elastically scattered deuterons were recorded simultaneously with the αK+K− events. Here we report about the luminosity determination via investigating the (quasi-) elastic deuterons at ANKE.

Measurement of the isospin-filtering dd → 4He K+K- reaction at Q = 39 MeV

The total cross-section for the dd → 4HeK+K− reaction has been measured at a beam momentum of 3.7GeV/c, corresponding to an excess energy of 39MeV, which is the maximum possible atthe Cooler Synchrotron COSY-Jülich. A deuterium cluster-jet target and the ANKE forward magnetic spectrometer, placed inside the storage ring, have been employed in this investigation. We find a total cross-section of σtot < 14 pb, which brings into question the viability of investigating the dd → 4He a0(980)reaction as a means of studying isospin violation.