Synthesis of Zirconia Nanoparticles in Distilled Water Solution by Laser Ablation Technique

Pulsed laser ablation in liquid （PLAL） has become an increasingly important technique for metals production and metal oxides nanoparticles （NPs） and others. This technique has its many advantages compared with other conventional techniques （physical and chemical）. This work was devoted for production of zirconia （ZrO2） nanoparticles via PLAL technique from a solid zirconium target immersed in a wet environment in order to study the effect of this environment on the optical properties and structure of ZrO2 nanoparticles. The solutions which used for this purpose is distilled water （D.W）. The produces NPs were characterized by mean of many tests such as UV-visible （UV-Vis.）, transmission electron microscope （TEM） and Z-Potential. The UV-Vis. A spectrum has atwavelength is 271 nm. The TEM test shows less than 10 nm average particle sizes with spherical and irregular shapes. Z-Potential test shows value about ＋56.1 mV which indicate for NPs stability with extremely low agglomeration solution.     

脉冲激光液相烧蚀贵金属Au/Ag产物的表征及反应机理研究

采用多波长(1064nm、532nm、248nm)脉冲激光在去离子水中对责金属Au、Ag片表面进行激光烧蚀(PLA).利用TEM、AFM、SEM对烧蚀金属片表层及产物(微/纳米尺度的金属颗粒)进行观察分析,认为在液相水环境中,整个烧蚀过程主要可分为激光诱导相沸腾爆炸和等离子体羽辉混合体膨胀2个过程.在这2个过程中分别产生得到具有微米尺度的球状金属颗粒和纳米尺度的金属颗粒.同时,具有纳米尺度金属Au/Ag颗粒经过强激光光子"二次"修饰改性过程,形成具有形状统一、分散性和稳定性较好的金属纳米胶体体系,这些胶体中金属纳米颗粒作为探针,在表面增强拉曼散射(SERS)光谱学方面有很好的应用价值.     

Photoconductive and photovoltaic evaluation of In2O3-SnO2 multilayered thin-films deposited on silicon by reactive pulsed laser ablation

In₂O₃ and SnO₂ multilayered semiconducting thin-films have been deposited on Si substrates by reactive pulsed laser ablation (RPLA), with the aim of evaluating their photoconductive and photovoltaic properties. A photo-stimulated electrical study has been performed on the films as a function of oxygen pressure during the deposition process and compared to their microstructure. Temperature-dependent resistivity measurements have been performed to determine the charge carrier transport mechanisms. The experimental demonstration of active photogeneration has been achieved and the influence of deposition parameters on the film structural properties has been correlated to the photovoltaic performance (open-circuit voltage, short-circuit current and output power).     

脉冲激光气相沉积技术现状与进展

介绍了脉冲激光沉积法(PLD)制备薄膜技术的原理、特点和这一研究领域的现状,着重介绍了脉冲激光沉积薄膜技术的研究动态和进展情况。大量研究表明,脉冲激光沉积法是一种最好的制备薄膜的方法之一。     

反应激光脉冲沉积法制备CoO和Co_3O_4薄膜

利用反应脉冲激光沉积法,以金属钴为靶材,通过改变衬底温度、反应气体氧气的流量等工艺参数,先后在玻璃衬底上成功制备了CoO薄膜以及Co3O4薄膜。通过X射线衍射（XRD）、X射线光电子能谱（XPS）、紫外-可见光吸收光谱（UV-Vis）研究了沉积工艺参数对沉积薄膜的晶体结构和光学特性的影响。结果表明,当氧气流量小于15sccm时,沉积的薄膜为岩盐矿结构的CoO,而当氧气流量大于15sccm时,沉积的薄膜为尖晶石矿结构的Co3O4。通过对紫外-可见吸收光谱的数据分析,证明CoO和Co3O4薄膜均为间接能带结构,禁带宽度分别为0.82eV和1.21eV。     

Luminescence hydrogenated nanoamorphous Si films fabricated by reactive pulsed laser ablation

Hydrogenated nanoamorphous Si (na-Si:H) films have been fabricated by reactive pulsed laser ablation technique with hydrogen as reactive gas. It is found that the hydrogen pressure has a great effect on both the structure and photoluminescence (PL) properties of the films. Increasing the hydrogen pressure leads to a structural transition of the films from amphorous Si to na-Si:H, and the PL center wavelength of the na-Si:H films is varied with the hydrogen pressure. The PL decay times of the na-Si:H films are in the nanosecond scale and are shorter on the high energy side of their PL spectrum. The results demonstrate that the na-Si:H films are promising candidates for visible, tunable and high-performance light-emitting devices.     

纳米颗粒的短脉冲激光烧蚀制备及其非线性光学应用

本文主要介绍了纳米颗粒的短脉冲激光制备及其在非线性光学领域的应用。短脉冲激光制备纳米颗粒具有纯度高、操作简单和适用性广等优点,所制备的非线性纳米颗粒尺寸分布均匀,粒度小且可调控,在非线性光学材料中有着独特的地位。为了更深入地对此进行研究,本文介绍了纳米颗粒的光学非线性和激光的特点和原理。在此基础上,通过阐述短脉冲激光与物质相互作用的机理,说明了激光制备纳米颗粒所具有的优点,详细分析了制备条件对合成纳米颗粒的影响,并结合激光制备不同的纳米颗粒,介绍当前激光制备各类纳米颗粒的研究现状。激光制备纳米颗粒是一种操作简便、适用性广,且对环境友好的方法。

     

硼和富硼氧化物在激光及高压处理后的结构和表征

采用激光蒸发及高温高压方法研究单质硼及高温高压合金的富硼氧化合物。结果表明,在激光作用下单质硼溅射粉末中存在Ｂ１２正二十面体硼笼;高温高压合成的高硼低氧化物在激光作用下再氧化,表现出特有的耐高温,抗氧化的特性。     

等离子体辅助反应式脉冲激光熔蚀制备AlN薄膜的低温生长

使用等离子体辅助反应式脉冲激光溅射沉积薄膜的方法在Ｓｉ（１１１）和Ｓｉ（１００）基片上已经成功地低温制备出ＡｌＮ多晶膜。实验表明,当脉冲能量密度ＤＥ＝１．０Ｊ·ｃｍ－２,脉冲频率ｆ＝５Ｈｚ,氮气气压ＰＮ２＝１．３３×１０４Ｐａ,基底温度ｔｓｕｂ＝２００℃,放电电压Ｖ＝６５０Ｖ,基靶距离ｄＳ－Ｔ＝４ｃｍ时薄膜的生长速度等于６ｎｍ／ｍｉｎ。ＡｌＮ薄膜的折射率为２．０５,和基底的取向关系分别为：ＡｌＮ（１１０）∥Ｓｉ（１１１）和ＡｌＮ（１００）∥Ｓｉ（１００）。     

脉冲激光法原位制备纳米二氧化硅杂化聚苯胺研究

用脉冲激光轰击法连续制备聚苯胺原位修饰的纳米二氧化硅,通过溶剂转换的方法,制备得到聚苯胺/纳米二氧化硅杂化薄膜材料,用标准四探针电性能测试,TEM、UV-Vis、TG、XRD、XPS等手段对其进行表征,探讨了纳米二氧化硅的加入对聚苯胺热、电方面产生的影响,结果表明,用本方法制备的纳米二氧化硅具有较小粒径,不团聚,能较好地分散于聚苯胺中与之形成杂化材料,纳米二氧化硅与聚苯胺分子链存在强烈的相互作用,破坏了聚苯胺的规整堆积,导致其热分解温度下降,导电载流子的浓度及迁移率减少,电导率值下降,而抗氧化性有所提高。     

环境气体对激光烧蚀制备纳米Si晶粒平均尺寸的影响

采用脉冲激光烧蚀装置,在不同环境气体下,沉积制备了含有纳米Si晶粒的薄膜.利用扫描电子显微镜(SEM)观察样品的表面形貌,并对晶粒尺寸进行统计分析,发现不同环境气体下,纳米Si晶粒平均尺寸均随衬底与靶的距离增加有着先增大后减小的规律;通过分析比较,同等条件下Ne气环境下制备的纳米Si晶粒平均尺寸最小.     

沉积位置对脉冲激光沉积纳米Si晶薄膜微观结构的影响

在4.0×10-4Pa的真空条件下,采用脉冲激光烧蚀技术在单晶Si衬底和石英衬底上制备了非晶纳米Si薄膜.在N2气氛下,经过900℃热退火得到纳米Si晶薄膜.采用表面台阶测试仪、扫描电子显微镜、拉曼光谱仪等检测手段对样品不同位置的微观结构进行了表征.测量结果表明制备的纳米Si晶薄膜厚度及其晶粒尺寸分布不均匀,随着测量点与样品沉积中心距离的增加,薄膜的厚度逐渐减小,纳米Si晶粒的尺寸逐渐增大.从脉冲激光烧蚀动力学的角度对实验结果进行了定性的分析.     

Effect of 80 keV Ar+ implantation on the properties of pulse laser deposited magnetite (Fe3O4) thin films

Highly oriented thin films of Fe₃O₄ were deposited on (100) LaAlO₃ substrates by pulsed laser ablation. The structural quality of the films was confirmed by X-ray diffraction (XRD). The films showed a Verwey transition near 120 K. The films were subjected to 80 keV Ar⁺ implantation at different ion doses up to a maximum of 6 × 10¹⁴ ions/cm². Ion beam induced modifications in the films were investigated using XRD and resistance vs temperature measurements. Implantation decreases the change in resistance at 120 K and this effect saturates beyond 3 × 10¹⁴ ions/cm². The Verwey transition temperature,T _V, shifts towards lower temperatures with increase in ion dose.     

液相脉冲激光轰击石墨制备碳纳米材料研究进展

碳纳米材料具有特殊的力学、电学及物化性能,在微电子、航空航天、军用材料等领域具有广阔的应用前景,利用脉冲激光高效、可控制备新型碳纳米材料已成为研究热点。简要介绍了激光与碳材料的相互作用及纳米粒子的成形机理,详细阐述了液相脉冲激光制备纳米金刚石、碳纳米管、石墨烯等碳纳米材料的过程及其影响因素,并展望了激光轰击石墨制备碳纳米材料的主要研究方向。