磁控溅射金属预置层后硒化法制备CuInSe_2薄膜工艺条件的优化

采用四因素四水平的正交实验法优化了磁控溅射金属预置层后硒化法制备CuInSe2 薄膜的工艺条件 .调节四个较为重要的影响因素 ,即Cu/In比、硒化时间、硒化温度和硒源温度制备得到 16个CuInSe2 样品 .用Hall效应仪对薄膜的电学性能进行了研究 ,并且通过XRD研究了薄膜的结构性能 .得到了制备具有较好电学性能的CuInSe2 薄膜的优化条件为 :Cu/In比 1 133,硒化温度 4 2 0℃ ,硒化时间 2 0min ,硒源温度 2 0 0℃ .在此优化条件下得到的薄膜Hall迁移率可以达到 3 19cm2 /(V·s) ,XRD结果表明薄膜中没有杂相存在 .     

硒化温度对Cu(In, Al)Se2薄膜结构和光学性质的影响

采用了磁控溅射制备Cu-In-Al金属前驱体薄膜,后硒化快速退火得到铜铟铝硒(Cu(In,Al)Se2,CIAS)薄膜.研究了硒化温度对CIAS薄膜晶体结构和光学性质的影响.研究发现CIAS薄膜的晶体结构依赖于硒化温度,其禁带宽度随硒化温度升高发生红移.研究结果表明,CIAS薄膜的最佳硒化温度为540℃,其晶体结构为纯黄铜矿结构,禁带宽度为.34 eV,对应太阳电池理论最大效率的吸收层材料禁带宽度     

周期顺序蒸发工艺生长的Cu(In,Ga)Se_2薄膜结构

采用新颖的周期顺序蒸发和真空硒化退火工艺生长出p型CuIn0 7Ga0 3 Se2 薄膜.通过XPS谱、Raman谱、XRD谱分析了预生长层以及硒化后的CuIn0 7Ga0 3 Se2 薄膜,对四元化合物Cu(In ,Ga)Se2 的Raman谱进行了讨论,并观察到Ga对A1模式峰位的移动影响,同时发现薄膜倾向于沿(112 )晶面生长,薄膜贫Cu会加剧(2 2 0 ) / (2 0 4)表面自发分解成{ 112 }小晶面.研究表明,薄膜具有良好的电学特性和结构特性.     

CuInSe2薄膜的化学溶液制备方法

采用了一种低成本化学溶液法制备铜铟硒(CuInSe_2,CIS)薄膜.研究了预退火温度、硒化温度及基片衬底等实验参数对材料性能的影响.采用硝酸铜和氯化铟配置前驱体溶液,旋涂法制膜,后经480℃硒化退火得到CIS薄膜.XRD测试结果表明薄膜结晶性良好,具黄铜矿结构;SEM测试结果显示薄膜由较大晶粒组成,表面相对平整致密;EDX测试显示薄膜组分相对合理,略贫Cu而富Se.采用此薄膜为吸收层制备CIS原型薄膜太阳能电池,其光电测试显示单层CIS光伏响应达到1.6%.     

周期顺序蒸发工艺生长的Cu(In,Ga)Se2薄膜结构

采用新颖的周期顺序蒸发和真空硒化退火工艺生长出p型CuIn0.7Ga0.3Se2薄膜.通过XPS谱、Raman谱、XRD谱分析了预生长层以及硒化后的CuIn0.7Ga0.3Se2薄膜,对四元化合物Cu(In,Ga)Se2的Raman谱进行了讨论,并观察到Ga对A1模式峰位的移动影响,同时发现薄膜倾向于沿(112)晶面生长,薄膜贫Cu会加剧(220)/(204)表面自发分解成{112}小晶面.研究表明,薄膜具有良好的电学特性和结构特性.     

三源真空蒸发CuInSe_2薄膜的性能

详细分析讨论了用三源真空蒸发法制取CuInSe2薄膜过程中，源温、衬底温度及Cu，In原子比值对薄膜性能的影响。     

MOCVD生长的全组分InGaN材料

利用金属有机物化学气相淀积(MOCVD)方法在C面蓝宝石衬底上制备了全组分InGaN薄膜,通过改变生长温度和In/Ga比例成功调控了InGaN合金组分和带隙宽度。利用不同的物理表征手段系统研究了InGaN薄膜的晶体结构和光电学性质,XRD和Hall等测试结果表明:富Ga的InGaN薄膜具有较好的晶体质量,背景电子浓度基本均比富In的InGaN低一个数量级。同时,结合光致发光谱和光学透射谱研究了InGaN合金带隙随In组分的变化关系。     

调整VO2薄膜相变特性和TCR的制备及辐照方法

采用不同的真空还原时间、真空退火温度和衬底制备出了VO2薄膜,并对制备出的薄膜进行电子辐照.通过测试辐照前后的VO2薄膜相变电学性能及低温半导体相电阻温度系数(TCR),表明不同的制备工艺和不同注量的电子辐照可明显改变VO2薄膜相变过程中电学性能,提高薄膜的电阻温度系数.对影响VO2热致相变薄膜电学性能及电阻温度系数的因素进行了讨论.     

硒化温度对SnSe2薄膜材料性能的影响

采用射频磁控溅射加硒化的两步法在超白玻璃衬底上生长SnSe₂薄膜,采用XRD、光学透过谱、Raman光谱、XPS和SEM等方法对薄膜进行性能表征。通过设置不同的硒化温度,研究不同硒化温度对所得薄膜相结构、物相与组分、表面形貌等性能的影响。结果表明:350℃,40min硒化所得薄膜为片状晶粒,光学带隙为1.46eV,相结构和均匀性等性能在该硒化条件下均为最佳。     

衬底温度对反应溅射ZnO：Al透明导电薄膜性能的影响

衬底温度在反应溅射制备ZnO：Al薄膜过程中是一个重要的工艺参数,直接决定这薄膜的性能。本文用中频脉冲磁控溅射方法,采用锌铝合金（Al的含量为2%）靶,在衬底温度170℃,工作压力2.5mTorr,氧氩比3/18的条件下,制备了ZnO：Al薄膜,利用X射线衍射仪对薄膜的结构进行了分析,利用分光光度计和四探针法测量了薄膜的光学和电学性能,研究了制备薄膜时不同的衬底温度对薄膜的结构、电学、光学性能的影响,结果表明,随着衬底温度的升高,薄膜的电阻率先下降后上升,而可见光范围平均透过率在85%以上,当衬底温度为170℃,工作压力2.5mTorr,氧氩比3/18时,薄膜电阻率最低为2.16×10-4Ωcm,方块电阻30Ω时,在可见光光范围内平均透过率高于85%。     

Nanostructured Surfaces by Deposition of Metal Nanoparticles by Means of Spray Techniques

An electrospray unit was built in order to deposit preformed metal nanoparticles on various substrates. Furthermore, due to treatment of the deposited particles with an oxygen plasma, the particles were stripped of their ligands and strongly fixed to the surface. These treated surfaces can be expected to exhibit properties that differ characteristically from bare surfaces. Depending on the substrate itself, but even more on the size and the density of the deposited nanoparticles, the contact angles and thereby the wettability could be varied drastically. Gold nanoparticles of 17 nm diameter on titanium decreased the contact angle from 82° to 34°, whereas 6–8 nm palladium particles increased the wettabilty to such a degree that a contact angle could not be determined. In contrast to the electrospray technique, a pneumatically operated device was constructed, allowing simultaneous spraying and plasma pyrolysis.     

激光裂解钛酸酯改性聚硅氧烷制备陶瓷涂层

为了解决先驱体转化陶瓷法中金属粉末活性填料在制备陶瓷涂层中分散不均的问题,采用激光裂解钛酸四丁酯改性聚二甲基硅氧烷法在金属基体表面制备陶瓷涂层,通过电子显微镜、X射线衍射和X射线光电子能谱等手段,取得了涂层表面并分析了激光裂解钛酸四丁酯改性聚二甲基硅氧烷生成物的组成与结构。结果表明,钛酸四丁酯添加量的质量分数为0.05时,涂层表面不同区域的Ti相对含量均在3%左右,Ti元素在涂层中分布均匀,钛酸四丁酯改性聚二甲基硅氧烷在激光作用下生成的陶瓷涂层主要由晶态的SiC,TiO₂,非晶态SiO₂,（TiO₂）₅₆（SiO₂）₄₄以及C₆H₁₈OSi₂等组成,激光裂解过程中新生的TiO₂,（TiO₂）₅₆（SiO₂）₄₄等陶瓷相对所制备的陶瓷涂层表面孔隙具有填补作用,使陶瓷涂层表面均匀平整致密,孔隙、缝隙基本消失,解决了金属粉末活性填料的分散问题。     

Modulations of laser signals by water waves observed by a boxcarintegrator

This paper describes a new measurement technique for active remote sensing of water waves using a lidar. To demonstrate this technique, a series of experiments studying interactions of laser pulses with water waves was performed in an NRL wave tank. This technique used a commercially available boxcar integrator to sample IR laser pulses reflected from water waves. These water waves were generated either by artificial winds or a mechanical paddle in the wave tank. The boxcar integrator samples these laser waveforms as a function of windspeeds and paddle frequencies. This paper describes the experimental technique, the measurements, and the data analyses. For wind-generated water waves, results of the data analyses show that lidar-detected laser energies and the lidar-detected water-wave frequencies are functions of windspeeds. For paddle waves, the measurement data show that the laser backscattering cross-section from a water wave is a function of height positions within the water wave. The measurement data successfully demonstrate a boxcar-integrator waveform-sampling technique as an alternative technique to, and possible improvement over, a conventional waveform digitizer. The potential application of this technique in active remote sensing is discussed     

Scattering of Electromagnetic Waves by Arrays of Conducting Cylinders Interspaced by Inhomogeneous Dielectrics

The scattering and transmission properties of arrays of rectangular conducting cylinders interspaced by homogeneous and inhomogeneous dielectric materials are studied by a fimite-difference coupling method for an E-polarized incident wave. Computed numerical results are presented which reveal interesting physical phenomena.     

用多次曝光全息透镜作散斑编码的图像处理

制备了一种新的全息光学透镜——MEHL.用该透镜实现了散射编码的白光图像处理.还可用于狭缝一步彩虹术中.     

Electromagnetic scattering by a curved plate--Solution by uniform asymptotic theory of diffraction

The uniform asymptotic theory (UAT) of diffraction has been applied to find the monostatic scattered field by curved plate with a plane wave illumination with electric field parallel to the edge. The solution is valid for all positions of the receiver and is uniform around the reflection boundaries. The theoretical monostatic radar cross section (RCS) shows good agreement with experimental results. The formulation works very well for arbitrary radius of curvature of the plate down to a value oflambda/2.     

Acceleration of Crystallization Kinetics in Ge-Sb-Te-Based Phase-Change Materials by Substitution of Ge by Sn

Thin films of (Ge_1–xSn_x)₈Sb₂Te₁₁ are prepared to study the impact of Sn-substitution on properties relevant for application in phase-change memory, a next-generation electronic data storage technology. It is expected that substitution decreases the crystallization temperature, but it is not known how the maximum crystallization rate is affected. Ge₈Sb₂Te₁₁ is chosen from the (GeTe)_y(Sb₂Te₃)_1–y system of phase-change materials as a starting point due to its higher crystallization temperature as compared to the common material Ge₂Sb₂Te₅. In situ X-ray diffraction at 5 K min⁻¹ heating rate is performed to determine the crystallization temperature and the resulting structure. To measure the maximum crystallization rate, femtosecond optical pulses that heat the material repetitively and monitor the resulting increase of optical reflectance are used. Glasses over the entire composition range are prepared using a melt-quenching process. While at x = 0, 97, subsequent pulses are required for crystallization, one single pulse is enough to achieve the same effect at x = 0.5. The samples are further characterized by optical ellipsometry and calorimetry. The combined electrical and optical contrast and the ability to cycle between states with single femtosecond pulses renders Ge₄Sn₄Sb₂Te₁₁ promising for photonics applications.     

Restoration of signals degraded by impulse noise by means of a low-distortion non-linear filter

A simple low-distortion non-linear filter for the restoration of signals degraded by random impulsive noise is proposed. It performs considerably better than a median filter, lowering the reproducing error both in mean-square and maximum-error sense, although being comparable in computing time and in terms of storage.