超导薄膜不仅在超导应用方面扮演着举足轻重的角色, 而且是超导机理研究的良好载体, 是连接超导应用和机理的桥梁。脉冲激光沉积(PLD)是最常用的超导薄膜制备技术之一。本文综述了PLD技术制备铜氧化物、铁基、氮化物、钛氧化物等超导薄膜的研究进展, 并介绍了与高温超导薄膜应用相关的两种PLD新技术: 超导带材和大面积薄膜制备。最后, 本文介绍了基于材料基因工程的高通量组合薄膜技术在高温超导研究上的典型成功案例。继续发展和使用该实验技术, 构建与高温超导相关的高维相图和定量规律, 有望实现机理研究实验上从量变到质变的全面突破。

Epitaxial VO₂ films grown by pulsed laser deposition (PLD) method with superior phase transition related switching characteristics are successfully embedded to SAW devices using concept of the “impedance loaded SAW sensor”. A resistance of VO₂ sensor abruptly drops from 0.7 MΩ to 90 Ω when it is heated above ∼65∘C and shows a narrow hysteresis loops when switching. Two designs of SAW devices are examined in which RF signal is reflected back from interdigital transducer (IDT) or a surface acoustic waves (SAW) is transferred through a coupler and the RF response is altered 2 and 3 times correspondingly upon the phase transition in VO₂. In the proposed devices with external load, a SAW does not propagate via VO₂ film and therefore is not attenuated which is beneficiary for wireless applications. Additionally, a SAW phase shift as great as 50∘ is induced to the SAW transferred through the coupler due to the phase transition in VO₂. The proposed approach may boost the development of remotely controlled autonomous sensors, including those based on VO₂ metamaterials and hybrid plasmonic structures for near IR/middle IR and sub-THz/THz applications.Epitaxial VO₂ films grown by pulsed laser deposition (PLD) method with superior phase transition related switching characteristics are successfully embedded to SAW devices using concept of the “impedance loaded SAW sensor”. A resistance of VO₂ sensor abruptly drops from 0.7 MΩ to 90 Ω when it is heated above ∼65∘C and shows a narrow hysteresis loops when switching. Two designs of SAW devices are examined in which RF signal is reflected back from interdigital transducer (IDT) or a surface acoustic waves (SAW) is transferred through a coupler and the RF response is altered 2 and 3 times correspondingly upon the phase transition in VO₂. In the proposed devices with external load, a SAW does not propagate via VO₂ film and therefore is not attenuated which is beneficiary for wireless applications. Additionally, a SAW phase shift as great as 50∘ is induced to the SAW transferred through the coupler due to the phase transition in VO₂. The proposed approach may boost the development of remotely controlled autonomous sensors, including those based on VO₂ metamaterials and hybrid plasmonic structures for near IR/middle IR and sub-THz/THz applications.

随着光通信技术与光子集成电路的发展, 非互易性器件作为光通信系统中重要的组成部分得到了越来越广泛的研究与应用。基于磁光效应制成的磁光隔离器和环行器是目前应用最为广泛的非互易性器件, 为了将非互易性器件整块集成在硅片上, 需制备性能与块状磁光材料相当的磁光薄膜。在近红外通信波段(1 550 nm), 以钇铁石榴石(Y3Fe5O12, YIG)为代表的稀土铁石榴石(RIG)具备优良的磁光效应, 是最具应用前景的磁光材料之一。研究发现, 使用稀土离子对YIG薄膜进行掺杂可以有效改善其磁光性能, 尤其是Bi3+和Ce3+掺杂的YIG表现出巨法拉第效应。本文首先介绍了法拉第效应原理, 介绍了三种常见磁光薄膜的生长方法, 回顾了近年来的主要研究成果, 介绍了磁光薄膜在光隔离器和环行器中的应用, 最后对磁光薄膜的未来发展趋势进行了展望。

This paper reports the impact of the laser pulse repetition frequency on growth processes, morphological and electro-physical parameters of nanocrystalline LiNbO₃ thin films obtained by the pulsed laser deposition technique. It was found that the nucleation process in LiNbO₃ films could controllably change by increasing the laser pulse repetition frequency. The film obtained at the repetition frequency of 4 Hz consists of local islands and clusters with a diameter of 118.1 ± 5.9 nm. Nanocrystalline films, grown at the repetition frequency of 10 Hz, possess a continuous granular structure with a grain diameter of 235 ± 11.75 nm. Achieved results can be used for the development of promising “green” energy devices based on lead-free piezoelectric energy harvesters.This paper reports the impact of the laser pulse repetition frequency on growth processes, morphological and electro-physical parameters of nanocrystalline LiNbO₃ thin films obtained by the pulsed laser deposition technique. It was found that the nucleation process in LiNbO₃ films could controllably change by increasing the laser pulse repetition frequency. The film obtained at the repetition frequency of 4 Hz consists of local islands and clusters with a diameter of 118.1 ± 5.9 nm. Nanocrystalline films, grown at the repetition frequency of 10 Hz, possess a continuous granular structure with a grain diameter of 235 ± 11.75 nm. Achieved results can be used for the development of promising “green” energy devices based on lead-free piezoelectric energy harvesters.

在不同氧分压下，用脉冲激光沉积法在c-蓝宝石衬底上制备了高质量β-Ga₂O_3-δ薄膜。通过X-射线衍射、远红外反射光谱、X-射线光电子能谱和紫外-可见-近红外透射光谱系统地研究了β-Ga₂O_3-δ薄膜的晶格结构、化学计量比和光学性质。X-射线衍射分析表明，所有沉积的薄膜以（-201）晶向方向生长。透射光谱显示薄膜在255 nm以上的紫外-可见-近红外波段具有80%以上的高透明度，同时在255 nm附近有一个陡峭的吸收边。此外，利用Tauc-Lorentz（TL）色散函数模型和Tauc公式，我们提取了β-Ga₂O_3-δ薄膜的光学常数和光学直接带隙。更进一步，我们通过理论计算解释了氧气分压对β-Ga₂O_3-δ薄膜光学性质的影响。

高质量氧化镓薄膜的获得是实现高性能氧化镓电子和光电子器件的重要前提条件之一。采用脉冲激光沉积技术,在室温下蓝宝石衬底上沉积氧化镓薄膜,并在氧气氛围下进行不同温度的退火,研究氧化镓薄膜特性的变化规律。结果表明:室温下沉积的氧化镓薄膜为非晶态,随着退火温度的升高,薄膜结晶程度变高,禁带宽度变大;退火前后氧化镓薄膜中都存在两种氧化价态镓,说明薄膜处于晶格氧缺失的状态;随着退火温度的升高,低价态镓比例减少,晶格氧的比例增加,薄膜质量升高;然而,过高的退火温度导致衬底中的铝扩散进入薄膜,薄膜质量变差,室温下生长的薄膜质量较差且与衬底之间的热膨胀系数和晶格失配,导致氧化镓薄膜高温退火时出现开裂的现象。

介绍了一种基于多脉冲模式的皮秒激光脉冲沉积方法，采用该方法在玻璃基底和单晶硅基底上沉积了透明导电氧化锌(ZnO)薄膜，使用光谱椭偏仪、原子力显微镜、扫描电子显微镜、X射线衍射仪、分光光度计和四探针测试仪分析了激光的不同脉冲串模式对ZnO薄膜厚度、粗糙度、表面形貌、晶体结构、光学性能以及电学性能的影响。结果表明：沉积速率随着子脉冲串数量的增加而减小；随着子脉冲串数量的增加，薄膜表面粗糙度减小，颗粒尺寸减小，薄膜变得更加致密光滑；所有样品均呈现多晶结构；ZnO薄膜的透过率在可见光区域内高于92.95%，且禁带宽度在3.317～3.427 eV范围内；薄膜电阻率随着子脉冲数量的增加而减小。相比于单脉冲，利用多脉冲沉积产生的薄膜具有更高的表面质量、更好的光学性能和更低的电阻率。

集成电路(IC)芯片封装中小尺寸、细节距焊点采用的传统锡基钎料在服役过程中存在桥接、电迁移、金属间化合物等问题，在大电流、大功率密度的应用中受到限制。采用脉冲激光沉积 (PLD)技术，在覆铜陶瓷 (DBC) 基板上图形化沉积了多孔微米银焊点，用于替代传统的钎料凸点，并将其应用于Si芯片与DBC基板的连接。结果表明：采用不锈钢作为掩模，可沉积出500 μm及300 μm特征尺寸的疏松多孔银焊点阵列，银焊点呈圆台形貌；在250 ℃温度、2 MPa压力下热压烧结10 min，Si芯片与DBC基板连接良好，连接后的银焊点边缘的孔隙率为42%左右，银焊点中心区域的孔隙率为22%; 500 μm和300 μm特征尺寸的银焊点的连接接头的剪切强度分别为14 MPa和12 MPa；接头断裂主要发生在银焊点与芯片或DBC基板的连接界面处。

本文采用脉冲激光沉积(PLD)技术在p型4H-SiC衬底上, 制备出沿(403)择优生长的β-Ga2O3薄膜。结果表明, 衬底生长温度对β-Ga2O3薄膜的形貌、结构、组分, 以及生长机理都有重要影响。当生长温度由300 ℃升高至500 ℃时, 薄膜结晶质量随生长温度升高而提高, 当温度进一步升高到600 ℃时, 薄膜结晶质量变差, 这是由于在相对低温(500 ℃以下)阶段, 生长温度越高, 沉积在衬底上原子的动能越大, 越容易迁移, 使得β-Ga2O3薄膜主要按照二维生长模式进行生长, 薄膜结晶质量提高, 表现为随着生长温度升高, 粗糙度降低。但当温度上升到600 ℃时, 由于4H-SiC衬底和β-Ga2O3薄膜之间的热膨胀系数存在差异, 导致薄膜生长由主要以二维生长模式向三维岛状演变。基于p-4H-SiC/n-β-Ga2O3构筑的异质结太阳电池, 其标准测试条件下光电转换效率达到3.43%。