Studies on photoinduced effects in pulse-electrodeposited Ag/Hg-1212/CdSe hetero-nanostructures

Metal/superconductor/semiconductor (Ag/Hg-1212/CdSe) hetero-nanostructures have been fabricated using pulse-electrodeposition technique and are characterized by X-ray diffraction (XRD), full-width at half-maximum (FWHM) and scanning electron microscopy (SEM) studies. The junction capacitance of Ag/Hg-1212, Hg-1212/CdSe and Ag/Hg-1212/CdSe heterojunctions is measured in dark and under laser irradiation at room temperature. The nature of the junction formed and built-in-junction potentials were determined. The increase in carrier concentration across the junction due to photo-irradiation has been observed.     

国产物理实验用半导体激光器输出光谱特性研究

对国产物理实验用半导体激光器的输出光谱特性进行了多方面的实验研究，测量方法和所得结论可供厂家的实验人员参考。     

拉伸应变对Bi2223/Ag带材Ic不均匀性的影响

研究了Bi2223/Ag带材的Ic和n值沿带长方向的不均匀性在拉伸应变下的变化。结果表明,Ic和n值的大小并不是逐点一一对应的;当应变小于不可逆拉伸应变时,Ic随应变增加缓慢下降,n值随应变增加缓慢下降并有小幅震荡;Ic的均匀度随应变增加基本上没有变化,n值的均匀度随应变增加变好并有小幅振荡,而且变化范围很小。     

Magnetic characteristics of thin Ni films electrodeposited on n-Si(1 1 1)

The nanocrystalline Ni films were grown on n-Si(1 1 1) substrate by pulsed electrodeposition in non-aqueous NiCl₂ + methanol solution. The frequency of potential pulse was modulated during the deposition of Ni onto Si substrates. When the frequency varies from 20 to 900 Hz, the average size of Ni nanocrystallites varied in the ranges from 48 to 130 nm. In these cases, all Ni films have grown through a three-dimensional instantaneous nucleation followed by diffusion-limited growth. From X-ray diffraction measurement, it has been found that Ni(1 1 1) grows preferentially on the Si(1 1 1) substrates. The magnetic hysteresis loops for as-deposited films were measured by using VSM. As the angle θ between film plane and applied magnetic field varies from 0 to 90, the coercivity (H_c) and squareness (S) obtained from the magnetic hysteresis loops showed an opposite behavior. With the increase in θ, H_c increased but S decreased near linearly. We have also investigated the variation of H_c as a function of Ni nanocrystallite’s size. From VSM measurement, we could observe that the coercivities for the magnetic field applied perpendicular and parallel to the film plane increase up to the average size of 86 nm but begin to decrease over this size.     

有机半导体薄膜生长原位实时测量方法的研究

针对原位实时监测有机半导体薄膜生长情况的需求, 提出了差分反射光谱法与场效应晶体管法结合的光电联合测量方法, 设计研制了测量系统. 以并五苯有机分子为例, 通过自制底栅底接触式场效应管微结构, 实验测试了热蒸发法生长导电膜层过程中光电信号的演变与相互关联. 光谱信号显示, 并五苯以薄膜态结构进行生长, 光谱随生长进程变化显著. 实验数据与四相结构模型仿真结果的良好吻合, 表明因薄膜增厚引起干涉条件的改变是光谱变化的主因, 由此推算出薄膜生长速率为0.23 nm/min. 当薄膜等效厚度达到28 nm时, 场效应管的导电性显著增强, 标志着并五苯有效传输层的形成. 此后, 薄膜厚度持续增加, 但测试电流增长缓慢, 说明该结构进入电学特性饱和区. 光电联合法不仅有助于研究有机半导体薄膜的光谱信息、电学特性和薄膜结构之间的相互对应关系, 也为发展原位监测有机半导体薄膜制备过程, 探索最佳工艺提供了新的研究手段.     

Impact of proton irradiation with different fluences on the characteristics of InP/InGaAs heterostructure

ABSTRACT

The effect of traps to C–V and I–V plots of InP/InGaAs heterostructure with 3?MeV proton irradiation at different fluences has been discussed. After proton irradiation, the total reverse capacitance increases, which does not only include the variation of the depletion region width, but also the charging and discharging effect of traps. The total actual traps density N_SS of InP/InGaAs heterostructure could reach 13 orders of trap density, which is from the peak under reverse bias. The forward current is dominated by recombination current at low voltage and by the tunneling current at high voltage. The tunneling current and trap-assisted tunneling current are dominant in the reverse current.     

Bi2223/Ag高温超导带的侧向弯曲率对载流能力的影响

Bi2 2 2 3银包套超导带材是研制高温超导磁体和高温超导强电应用的基础。文中就对高温超导磁体最大运行电流有重要影响的 Bi2 2 2 3银包套带材侧向弯曲形变进行了初步探讨 ,就不同的侧向弯曲率对超导带载流能力的影响进行了实验测试 ,并提出了提高 HTS磁体最大运行电流的方法。     

电子辐照ITO/F46/Ag热控涂层的电学性能退化及损伤机理

对ITO/F46/Ag热控涂层进行了电子辐照地面模拟试验,探讨了其表面电阻率随电子辐照注量的退化规律,并借助扫描电镜（SEM）对其表面形貌变化进行了研究。通过SEM分析发现,涂层表面发生了严重的损伤效应,有裂纹、碎片和熔蚀现象出现。对涂层的损伤机理进行了分析,并给出了电子辐照ITO/F46/Ag热控涂层的表面碎裂损伤模型。     

Effect of gamma irradiation on HPMC/ZnO nanocomposite films

The present work looks into the structural, chemical, mechanical, optical and thermal modification in ZnO nanoparticle incorporated hydroxypropyl methylcellulose (HPMC) polymer films, induced by gamma irradiation. The irradiation process was performed in a gamma chamber at room temperature using Cobalt-60 source (average energy of 1.25?MeV) at different doses: 0, 50, 100, 150 and 200?kGy. The modifications in structural, chemical, mechanical, optical and thermal properties, due to gamma irradiation in HPMC/ZnO nanocomposite films, have been studied using wide angle X-ray scattering (XRD), Fourier transform infrared spectroscopy, universal testing machine, ultraviolet–visible spectrophotometry and thermogravimetric analysis. It is found that gamma irradiation improves the mechanical and thermal properties of nanocomposite films.     

Effect of reducing agent in the formation of CdSe nanoparticles by chemical reduction route

CdSe nanoparticles were synthesized using a simple chemical reduction route at room temperature. Nanoparticle size was controlled by the amount of reducing agent and was characterized by TEM and TED. With increased amounts of sodium borohydride as a reducing agent, the size of the nanoparticles decreased. Size of the nanoparticles varies between 5 and 12 nm with a size dispersion of 1.5 nm. The grown sample was ultra-sonicated in ethanol. The dispersed sample was characterized structurally, optically and electrically. The long-duration photoconductive decay at room temperature shows exponential variation under weak illumination.     

强激光照射对6H-SiC晶体电子特性的影响

使用基于密度泛函微扰理论的第一性原理赝势法, 模拟研究了纤锌矿6H-SiC晶体在强激光照射下电子特性的变化. 研究结果表明, 电子温度T_e在升高到3.89 eV及以上后, 6H-SiC由间接带隙的晶体变为直接带隙的晶体; 带隙值随电子温度T_e升高先是增大后又快速减小, 当电子温度T_e大于4.25 eV以后, 带隙已经消失而呈现出金属特性.     

Effect of gamma irradiation on synthesis and characterization of bio-nanocomposite SF/Ag nanoparticles

This study describes the synthesis of silver nanoparticles (AgNPs) using aqueous silk fibroin (SF) solution obtained from Bombyx mori silk under gamma radiation environment. The obtained AgNPs were characterized using UV–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD) measurements, dynamic light scattering experiment (DLS) and transmission electron microscope (TEM) images. The UV–Vis absorption spectra of the samples confirmed the formation of AgNPs by showing surface plasmon resonance (SPR) band in the range of (= 428–435?nm. The XRD study revealed metal silver with the face-centered cubic (FCC) crystal structure. DLS measurements showed the dose-dependent average size of the AgNPs. TEM images showed formed AgNPs are nearly spherical in shape with smooth edges. From this study, it was found that the increasing radiation dose increases the rate of reduction and decreases the particle size. The size of the AgNPs can be tuned by controlling the radiation dose.     

Effect of swift heavy ion irradiation in Fe/W multilayer structures

Present study reports effect of swift heavy ion irradiation on structural and magnetic properties of sputtered Fe/W multilayer structures (MLS) having bilayer compositions of [Fe(20 Å)/W(10 Å)]_5BL and [Fe(20 Å)/W(30 Å)]_5BL. These MLS are irradiated by 120 MeV Au⁹⁺ ions up to fluence of 4 × 10¹³ ions/cm². X-ray reflectivity (XRR), wide-angle X-ray diffraction (WAXD), cross-sectional transmission electron microscopy (X-TEM) and magneto optical Kerr effect (MOKE) techniques are used for structural and magnetic characterization of pristine and irradiated MLS. Analysis of XRR data using Parratt's formalism shows a significant increase in W/Fe interface roughness. WAXD and X-TEM studies reveals that intra-layer microstructure of Fe-layers in MLS becomes nano-crystalline on irradiation. MOKE study shows increase in coercivity at higher fluence, which may be due to increase in surface and interface roughness after recrystallization of Fe-layers.     

Effect of proton irradiation on the physical properties of PC/PBT blends

Samples from polycarbonate/poly (butylene terephthalate) (PC/PBT) blends film have been irradiated using different fluences (1?×?10¹⁵– 5?×?10¹⁷ H⁺/cm²) of 1?MeV protons at the University of Surrey Ion Beam Center, UK. The structural modi?cations in the proton irradiated samples have been studied as a function of fluence using different characterization techniques such as X-ray diffraction and UV spectroscopy. The results indicate that the proton irradiation reduces the optical energy gap that could be attributed to the increase in structural disorder of the irradiated samples due to crosslinking. Furthermore, the color intensity ΔE, which is the color difference between the non-irradiated sample and those irradiated with different proton fluences, increased with increasing the proton fluence up to 5?×?10¹⁷ H^+/cm², convoyed by an increase in the red and yellow color components. In addition, the resultant effect of proton irradiation on the thermal properties of the PC/PBT samples has been investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It is found that the PC/PBT decomposes in one weight loss stage. Also, the variation of transition temperatures with proton fluence has been determined using DSC. The PC/PBT thermograms were characterized by the appearance of two endothermic peaks due to the glass transition and melting temperatures. The melting temperature of the polymer, T_m, was investigated to probe the crystalline domains of the polymer, since the proton irradiation destroys the crystalline structure so reducing the melting temperature.     

退火温度对旋涂法制备SnO_2薄膜性能的影响

采用旋涂法在玻璃基底上制备SnO_2薄膜,通过原子力显微镜(AFM)、X射线反射(XRR)、傅氏转换红外线光谱仪(FT-IR)、X射线衍射(XRD)、紫外-可见分光光度计、四探针、开尔文探针系统对薄膜的表面形貌、结构及光学特性、电学特性进行分析,探讨了退火温度对薄膜质量的影响及作用机制。研究发现:随着退火温度升高,薄膜厚度和有机成分杂质减小,薄膜密度递增,但薄膜表面粗糙度有所上升;当退火温度升高至500℃时,薄膜结构由非晶转变为结晶,其主要晶面为氧化锡的(110)、(101)和(211)晶面。旋涂法制备的氧化锡薄膜在可见光区域的平均透光率在90%以上,随着退火温度上升,薄膜在400～800 nm波段的透光率先减小后增大,薄膜的带隙宽度分别为3. 840 eV(沉积态薄膜)、3. 792 eV(100℃)、3. 690 eV(300℃)和3. 768eV(500℃);薄膜的电导率也随着退火温度升高而增加,在500℃时电导率高达916 S/m;薄膜的功函数先增大后减小,分别为(4. 61±0. 005) eV(沉积态薄膜)、(4. 64±0. 005) eV(100℃)、(4. 82±0. 025) eV(300℃)、(4. 78±0. 065) eV(500℃)。     

辐照激光能量对SiO2薄膜特性及结构的影响

 为了认识SiO2薄膜在激光辐照下的变化,本文以K9玻璃为基底,采用电子束热蒸发方法制备了SiO2薄膜,并将此组在相同实验条件下制备的薄膜加以不同能量的激光辐照,研究在激光辐照前后样片的透射率、折射率、消光系数、膜厚、表面形貌及激光损伤阈值（LIDT）的变化。结果表明,样片膜厚随激光能量的增加而减小,辐照激光能改善薄膜表面形貌,并使样片LIDT值提高,最终能使样片的LIDT值从16.96 J/cm2提高至18.8 J/cm2。     

Effect of ion irradiation on C 60 thin films

We report a new effect of ion irradiation on C₆₀ thin films: C₆₀ thin films irradiated with 7-MeV C²⁺ ions show resistance to photopolymerization. The resistance increases with increasing ion fluence of irradiation. The effect is qualitatively explained by the fact that the number of a C₆₀ pair satisfying the topochemical requirement for photochemical reaction in solids decreases by destruction of C₆₀ molecules accompanied by lattice disorder.     

由缺陷引起的Burstein-Moss和带隙收缩效应对CdIn2O4透明导电薄膜光带隙的影响

在Ar+O2气氛，采用射频反应溅射Cd In靶制备CdIn2O4（CIO）薄膜.通过对不同衬底 温度下制备和沉积后在氩气流中退火的薄膜进行透射、反射和Hall效应的测量和分析发现， 随着衬底温度的降低，载流子浓度呈上升趋势，而吸收边呈现先是“蓝移”然后“红移”的 现象.从理论上阐述了高浓度的点缺陷对CIO氧化物薄膜的能带产生的重要影响，这些影响主 要体现在带尾的形成，Burstein Moss(B M)漂移和带隙收缩.另外，衬底温度的变化将对 薄膜的迁移率有重要影响.对于CIO薄膜，由缺陷产生的空穴浓度将对薄膜的带隙收缩产生重 要影响并将直接影响到薄膜的光透性.由于存在吸收带尾，利用传统的“外推法”获得薄膜 的光带隙并不适合简并半导体，而应使用更为准确的“拟合法”. 关键词： 射频反应溅射 CdIn2O4透明导电薄膜 Burstein Moss漂移 带隙收缩 电学性 质 光学性质     

衬底温度对磁控溅射法制备的Ag/AZO绒面背反电极性能的影响

通过优化薄膜硅基太阳能电池的背反电极,使背反电极表面出现均匀的类金字塔结构,能够增大入射光在结区的有效光程,提高光子的捕获率,进而会提高薄膜硅基太阳能电池的光电转换效率.本文采用磁控溅射技术在载玻片上制得Ag/AZO(ZnO∶Al)导电薄膜.在控制其它溅射参量为最优化的情况下,研究了衬底温度对Ag/AZO导电薄膜光电性能及其表面形貌的影响.研究表明:随着衬底温度的增加,薄膜的雾度在可见光范围内先增大后减小;当衬底温度为500℃时,雾度取得最大值,在可见光范围内平均达到了95％以上;电阻率随着衬底温度的增加逐渐增大,且衬底温度超过500℃时电阻率急剧增大.在综合考虑其光电性能的情况下,实验得到当衬底温度为500℃时,所获得的叠层薄膜表面雾度值最好且电阻率很小,这将有助于改善太阳能电池的性能.