稳定生长高透过大尺寸KCl单晶

上海光机所第八研究室,在用反应气氛法提纯KCI原料的基础上,通过对各种工艺参数(炉内装置、温度梯度、生长速度、气氛条件等)的控制和改进,已稳定生长出φ80×80mm以上的大块单晶.晶体的吸收系数(10.6μm)小于3×10~(-4)cm~(-1),接近国外最高水平.作为CO_2激光输出窗口,通过2kW以上的高功率激光,晶体窗口未见任何损伤.为提高KCl材料的激光破坏阈值,该室还进行了KCl单晶的热煅实验.摸索了热煅模具、煅压压力与温度、保压和退火时间等工艺条件,获得了晶粒度均匀的多晶片,热压多晶的抗折强度比单晶提高了4倍以上.     

单晶光纤的应用包括非线性光学效应

单晶光学纤维既保留了材料的性质，又具有波导的几何形状，无论玻璃光学纤维或体块单晶都不能达到这一要求。许多结晶材料(如蓝宝石)具有宽透过窗口、高熔点和抗化学侵蚀性，使它们在能量传输,特别是在有害的热化学环境应用中很有吸引力,一些晶体,如Nd:YAG和红宝石的荧光和激光增益特性,在传感器和小型激光器应用中很有用。     

准分子激光制备多层铁电薄膜的C—V特性研究

采用脉冲准分子激光工艺，在ｐ型Ｓｉ（１００）单晶基片上，成功地淀积了ＢＩＴ、ＰＺＴ／ＢＩＴ和ＢＩＴ／ＰＺＴ／ＢＩＴ等多层结构的铁电薄膜，采用低频阻抗分析仪，分析了它们的Ｃ－Ｖ特性曲线的记忆窗口，讨论了记忆窗口与频率的关系，记忆窗口与多层结构的关系。结果表明，三层结构铁电薄膜的Ｃ－Ｖ特性的窗口优于双层和单层结构的铁电薄膜。     

适合ArF准分子激光光刻的紫外光学材料

东北大学金属材料研究所的福田承生教授等找到了适合 Ar F准分子激光光刻的透镜、窗口材料Li Ca Al F6。高质量的 Li Ca Al F6单晶波长 1 93 nm的 Ar F准分子激光有望作为下一代光刻光源。然而 ,据称过去的透镜材料和窗口材料在这一波段却不能使用。研究组发现 ,新材料 Li Ca Al F6对紫外光有高承受能力 ,最短透过波长 1 1 2 nm,具有优异的紫外透过特性。 Li Ca Al F6加工性能优异 ,有望作为光学材料。试制的晶体大小如照片所示 ,预计能得到半导体曝光装置的透镜所需大小的晶体适合ArF准分子激光光刻的紫外光学材料@思源…     

基于单晶光纤的固体激光器研究进展

单晶光纤激光器在激光医疗、激光成像、光电对抗以及人眼安全测照等领域具有重大的应用价值,近年来成为新型固体激光源研究的热点.文章介绍了单晶光纤的制备方法,分析了单晶光纤激光器的工作原理,着重阐述了连续单晶光纤激光器、调Q单晶光纤激光器及种子注入单晶光纤激光放大器的技术方案和最新研究进展,讨论了单晶光纤激光器的优点和劣势,并对单晶光纤激光器的进一步发展进行了展望.     

GGG激光器输出230瓦

日本住友金属矿山公司使用GGG(钆-镓-石榴石）单晶作成片状激光器，获得230瓦的激光振荡。现在的固体激光元件以YAG单晶为主，然而要获得1千瓦以上的大功率激光，一般认为采用GGG单晶是有利的。此处以获得230瓦为契机，将加紧开发输出1千瓦用的激光材料。     

复合单晶被动调Q光纤激光器的制备与数值模拟

为了开发新型激光材料,采用激光加热基座法将Cr4 ∶YAG单晶光纤和Nd3 ∶YAG单晶光纤生长为一体化复合单晶光纤。利用速率方程理论,得到包含激光增益介质反转密度、光子密度和饱和吸收介质基态布居数密度的速率方程组。通过数值计算,求得复合单晶Cr4 被动调Q光纤激光器的若干重要特征参量及其与抽运率的函数关系曲线,计算结果较好地符合了实验结果,从而可以为优化设计这类单晶光纤激光器提供指导。     

Cr4+:YAG作饱和吸收体的被动Q开关复合单晶光纤激光器

采用激光加热基座法(LHPG)将Cr4 :YAG单晶光纤和Nd3 :YAG单晶光纤生长为一体化复合单晶光纤。进一步实验研究该单晶光纤的一些性质,表明它满足全固化被动调Q激光器的要求。已实现了脉宽10ns、最大平均输出功率达30mW、重复频率为16kHz的调Q激光。     

掺钕陶瓷激光器获得236 W高功率激光输出

随着1999年陶瓷制备工艺的突破性进展，透明陶瓷作为激光增益介质取得了可与单晶相比拟的光学质量。Nd：YAG单晶是目前应用最广泛的固体激光介质，然而传统提拉法生长的单晶的固有缺陷限制了它的进一步发展。     

稀土金属真空提纯炉的研制

介绍了一种用于稀土金属提纯的单晶炉,根据区熔法提纯单晶的特殊工艺要求,分析了其主要结构及特点。该设备也适用于多种激光晶体的生长和激光晶体的真空退火。     

CW laser annealing of boron implanted polycrystalline silicon

The electrical characteristics have been measured on CW laser annealed boron implanted polycrystalline silicon layers. It is shown, that a resistivity can be obtained, which is only about double that of a single crystalline layer doped to the same level. By appropriate choice of doping and laser annealing parameters, a temperature coefficient close to zero can be achieved. It is also shown that laser irradiation can be used to trim a furnace annealed polysilicon resistor to a desired resistance value.     

Nd：YAG多晶透明陶瓷的光谱性质

为了研究Nd:YAG多晶透明陶瓷作为激光增益介质的可能性,测量了掺杂原子数分数为1%的Nd:YAG多晶透明陶瓷的吸收光谱、荧光光谱、荧光寿命等光学参量,并和Nd:YAG单晶进行了比较。测量结果表明,Nd:YAG多晶透明陶瓷作为激光增益介质具有极大的潜力。     

Laser pattern-write crystallization of amorphous SiC alloys

The aim of this work is to investigate the cw-laser crystallization of amorphous a-Si_1−xC_x alloys as a function of laser power and alloy composition. As the microRaman analysis reveals, many cases occur: in a silicon rich alloy (x ∼0.3) we can obtain two crystalline phases, i.e. polycrystalline Si or polycrystalline C, depending on the laser energy density irradiated on the film. The presence of polycrystalline SiC is observed only in quasi-stoichiometric alloy (x ∼ 0.48) in the cubic β-SiC phase. The experiment has been performed with a laser pattern-writing system that permits simultaneous control of annealing energy and focused spot size. PC control allows several patterns to be traced on the same film.     

脉冲激光烧蚀沉积ZnSe薄膜的研究

用 2 48nm的KrF准分子脉冲激光烧蚀ZnSe靶材沉积ZnSe薄膜。靶采用多晶ZnSe片 ,衬底采用抛光GaAs(10 0 )。衬底预处理采用化学刻蚀和高温处理。原子力显微镜 (AFM )观察显示在GaAs(10 0 )沉积的ZnSe薄膜的平均粗糙度为 3～ 4nm。X射线衍射 (XRD)结果表明ZnSe薄膜 (4 0 0 )峰的半高宽 (FWHM)为 0 4°～ 0 5°。对激光烧蚀团束的四极质谱分析表明烧蚀团束主要由Zn ,Se和 2Se组成 ,并由此推断ZnSe薄膜的二维生长模式。     

Phase transformations initiated in thin layers of amorphous silicon by nanosecond excimer laser pulses

The reflection of a probing beam with a wavelength λ=0.63 μm from a silicon surface layer (a-Si) amorphized by ion implantation was detected during its melting and solidification initiated by excimer ArF laser radiation. When the irradiation energy is below the epitaxial threshold, a single event of a-Si layer melting leads to the formation of single nanocrystals separated from one another in the amorphous matrix rather than to the appearance of polycrystalline material. The presence of nanocrystals makes possible the formation of polycrystalline Si from a melt under exposure to a second laser pulse and allows the intermediate crystallization of Si in a laser-induced sequence of phase transitions. The data obtained are compared to the results of studying the phase transitions initiated in similar experimental conditions in thin layers of hydrogenated a-Si layers on glass substrates. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 37, No. 5, 2003, pp. 622–628. Original Russian Text Copyright ? 2003 by Ivlev, Gatskevich.     

含钪石榴石Nd:GSGG晶体的原料制备、晶体生长及结构研究

提拉法生长的Nd:GSGG是性能优良的激光晶体,在固体强激光领域有重要的运用前景.采用液相共沉淀法制备了GSGG的前驱物,将前驱物在较低的温度下烧结,获得了GSGG多晶原料,用提拉法生长了无散射、气泡、云层、无开裂的φ2626mm×45 mm的含钪石榴石Nd:GSGG晶体.用X射线衍射对GSGG的共沉淀前驱物在不同烧结温度下的相变情况进行了研究,表明在900℃烧结温度下,GSGG前驱物即可反应形成GSGG多晶,这比固相法合成GSGG料的反应温度低了200℃.同时,用X射线衍射对GSGG多晶、Nd:GSGG单晶的结构进行了研究,采用最小二乘法,以f(θ)=sin θ-sin1-Tθ(T=20)为外推函数,计算了GSGG多晶和Nd:GGG单晶的晶格参数,分别为1.257547 nm、1.256163 nm.它们之间的晶格参数差异可能是由于Ga组分的不同所引起的.     

A high density CMOS inverter with stacked transistors

This paper describes a complete CMOS inverter, whose P-channel transistor is made from laser annealed polycrystalline silicon and is superimposed upon the N-channel transistor. The single gate is common to both transistors. The process is NMOS compatible and polysilicon transistors with channel lengths down to 4 micrometers have been made.     

Integrated amorphous and polycrystalline silicon thin-filmtransistors in a single silicon layer

Using a masked hydrogen plasma treatment to spatially control the crystallization of amorphous silicon to polycrystalline silicon in desired areas, amorphous and polycrystalline silicon thin-film transistors (TFTs) with good performance have been integrated in a single film of silicon without laser processing. Both transistors are top gate and shared all process steps. The polycrystalline silicon transistors have an electron mobility in the linear regime of ~15 cm²/Vs, the amorphous silicon transistors have a linear mobility of ~0.7 cm²/Vs and both have an ON/OFF current ratios of >10⁵. Rehydrogenation of amorphous silicon after the 600°C crystallization anneal using another hydrogen plasma is the critical process step for the amorphous silicon transistor performance. The rehydrogenation power, time, and reactor history are the crucial details that are discussed in this paper     

KCl:Li FA(Ⅱ)色心激光晶体材料(综述)

本文以KCl:Li FA(Ⅱ)心为色心激光材料的代表,从材料物理化学的角度分析了KCl-LiCl以及与基质KCl有关的掺杂体系的性质,综述了掺Li+KClFA(Ⅱ)心的主要特性,总结色心激光晶体的制备.     

Graphene/Strontium Titanate: Approaching Single Crystal–Like Charge Transport in Polycrystalline Oxide Perovskite Nanocomposites through Grain Boundary Engineering

Grain boundaries critically limit the electronic performance of oxide perovskites. These interfaces lower the carrier mobilities of polycrystalline materials by several orders of magnitude compared to single crystals. Despite extensive effort, improving the mobility of polycrystalline materials (to meet the performance of single crystals) is still a severe challenge. In this work, the grain boundary effect is eliminated in perovskite strontium titanate (STO) by incorporating graphene into the polycrystalline microstructure. An effective mass model provides strong evidence that polycrystalline graphene/strontium titanate (G/STO) nanocomposites approach single crystal‐like charge transport. This phenomenological model reduces the complexity of analyzing charge transport properties so that a quantitative comparison can be made between the nanocomposites and STO single crystals. In other related works, graphene composites also optimize the thermal transport properties of thermoelectric materials. Therefore, decorating grain boundaries with graphene appears to be a robust strategy to achieve “phonon glass–electron crystal” behavior in oxide perovskites.