通过氧化Cu膜制备Cu_2O薄膜

通过热蒸镀Cu膜并在空气中退火制备Cu2O薄膜,利用X射线衍射(XRD)、能量分散X射线谱(EDX)和原子力显微镜(AFM)研究了已沉积和不同温度退火薄膜的晶体结构、成份和表面形貌。结果表明,Cu膜在200℃退火30分钟可以得到具有单一成份的Cu2O薄膜。四探针测量得到所制备的Cu2O薄膜电阻率为0.22Ωcm。用紫外可见光分光光度计(UV-vis)研究了Cu2O薄膜的光学特性,得出其光学带隙为2.4eV。     

SrTiO3斜切基片上外延生长YBa2Cu3O7-δ薄膜的扫描探针显微镜研究

采用激光脉冲沉积法在钛酸锶SrTiO3 (0 0 1)斜切基片上外延生长YBa2 Cu3 O7 δ薄膜 ,在大气环境下采用扫描探针显微镜对YBa2 Cu3 O7 δ薄膜的表面纳米形貌进行直接观察。发现YBa2 Cu3 O7 δ薄膜具有相对光滑的表面形貌 ,薄膜表面由沿SrTiO3台阶趋向外延生长的纳米台阶组成 ,薄膜生长模式主要以台阶媒体生长为主。     

氩离子刻蚀对TFA-MOD法YBa2Cu3O7-x薄膜性能的影响研究

TFA-MOD工艺制备的YBa₂Cu₃O_7-x(YBCO)薄膜有独特的生长机制, 高温晶化后的YBCO薄膜表面存在一层由Ba-Cu-O异质相及a轴生长的YBCO晶粒组成的杂质层。为了满足零电阻超导焊接和超导带材钎焊搭接的研究需要, 在不破坏超导特性和晶体结构的前提下, 采用Ar离子对TFA-MOD工艺制备的YBCO薄膜进行刻蚀, 对薄膜进行纳米级的减薄, 实现对薄膜表面杂质的去除。利用拉曼光谱、扫描电子显微镜和X射线衍射等方法对不同刻蚀时间下的薄膜状态进行表征。结果表明, 1.3 μm厚的YBCO薄膜表面杂质层厚度约为220 nm, 并且在过度刻蚀的情况下, YBCO薄膜仍然是c轴取向, 晶体结构没有被破坏。刻蚀后,薄膜内部氧空位缺陷的产生会造成超导转变及载流性能的降低, 但通过吸氧处理后薄膜性能可恢复。     

硫化物靶与单质靶制备Cu2ZnSnS4薄膜的比较研究

为了验证磁控溅射硫化物靶替代单质靶制备Cu₂ZnSnS₄(CZTS)薄膜及太阳电池的可行性与优越性, 采用多周期磁控溅射ZnS-Sn-CuS和Zn-Sn-Cu制备CZTS薄膜, 并分析了使用不同溅射靶材对薄膜晶体结构、相纯度、表面粗糙度、化学组分、表面、截面形貌及光电特性的影响。按SLG/Mo/CZTS/CdS/i-ZnO/ZnO:Al/Ni-Al结构制成完整的电池器件并测量了J-V曲线。结果显示采用ZnS-Sn-CuS靶制备的CZTS薄膜太阳电池开路电压为611 mV, 短路电流密度为21.28 mA/cm ², 光电转换效率达5.11%; 而以单质靶为基础制备的太阳电池开路电压为594 mV, 短路电流密度为18.56 mA/cm ², 光电转换效率为4.13%。这归因于采用ZnS-Sn-CuS制备的CZTS薄膜相比于单质靶更加平整致密, 纵向生长更好。证明了采用硫化物靶制备CZTS薄膜及太阳电池相较于单质靶的优越性。     

氧化钛薄膜电致变色性质研究

通过在循环伏安过程中对透过率的实时测定,研究了由水相溶胶－凝途径制得的ＴｉＯ２薄膜的电致变致变色特性,在Ｉｍｏｌ／ｄｍ＾３ＨＣｌ溶液中,经１５０℃和３５０℃处理的ＴｉＯ２薄膜在６３０ｍｍ处的着色效率分别为８．８、４．９ｃｍ＾２／Ｃ, 循环稳定性都较差,在１ｍｏｌ／ｄｍ＾３ＬｉＣｌＯ４的碳酸丙烯酯溶液中,经４５０℃处理的Ｔdisplay status     

Normal State Resistivity of Underdoped YBa2Cu3Ox Thin Films and La2-xSrxCuO4 Ultra-Thin Films under Epitaxial Strain

The normal state resistivity of high temperature superconductors can be probed in the region below T _c by suppressing the superconducting state in high magnetic fields. Here we present the normal state properties of YBa ₂ Cu ₃ O _x thin films in the underdoped regime and the normal state resistance of La _2-x Sr _x CuO ₄ thin films under epitaxial strain, measured below T _c by applying pulsed fields up to 60 T. We interpret these data in terms of the recently proposed 1D quantum transport model with the 1D paths corresponding to the charge stripes.     

直流反应磁控溅射法制备CdIn2O4薄膜的光电性能研究

利用直流反应磁控溅射法制备了CdIn2O4(CIO)薄膜,研究了氧浓度、基片温度、溅射时间和退火处理对薄膜光电性能的影响.结果表明电阻率随着氧浓度的增加和溅射时间的减小而增加,随着基片温度的升高先减小后增加;透光率随着氧浓度、基片温度的增加和溅射时间的减小而增加.退火处理后,薄膜的电阻率降低,光吸收边发生"蓝移".点缺陷对薄膜的光电性能产生重要影响,光吸收边的移动是"Burstein-Moss"效应和多体效应共同作用的结果.综合实验结果和理论研究,推荐了直流反应磁控溅射法制备CIO薄膜的最佳条件.此条件下制备薄膜的电阻率为2.95×10-4 Ω·cm,波长为628 nm时薄膜的透光率高达91.7%.     

Nanostructure Study of TiO2 Films Prepared by Dip Coating process

The microstructure properties of the sol-gel derived TiO2 films were studied by the atomic force microscopy(AFM).The films were prepared by dip coating process.The optical properties of the films were explained on the basis of the microstructure of the films.     

Magnetic Fieid-lnduced Recovery of Superconductivity in Epitaxial YBa2Cu3O7-x Films at Microwave Frequencies

An anomalous magnetic field-effect has been observed in the microwave surface impedance of epitaxial YBa₂Cu₃O_7−x films on LaAlo₃ substrates. The application of dc and microwave magnetic fields up to 20 mT caused a significant decrease of microwave surface reactanceX _s (≤3%) and resistanceR _s (≤20%) at 8.5 GHz, 77 K and at 87 GHz, 4.2 K. The field effects onX _s andR _s s were found to correlate within the framework of the two-fluid model. The observed effect is attributed to the presence of magnetic impurities in the superconducting films, giving rise to pair breaking. Alignment of the impurity spins suppresses the spin-flip scattering rate and, as a result, leads to a recovery of microwave superconductivity.     

Synthesis and Characterization of Doped YBa2Cu 4 O8 Superconductor by Cd+2

In this study, the effect of yttrium substitution by cadmium in the YBa₂Cu₄O₈ superconductor was investigated. A series of superconducting oxide ceramics of (Y_1?x Cd _x )Ba₂Cu₄O₈ with a different Cd content (x=0.00–0.18 mol) were prepared by an aqueous sol-gel method using aqueous mixtures of the metal acetates. Homogeneous precursor gels were obtained by complexing copper ions with tartaric acid. The obtained gel powders and end products were characterized by X-ray powder diffraction analysis, infrared spectroscopy, thermal gravimetric analysis, differential thermal analysis, scanning electron microscopy, energy of dispersive X-ray analysis, DC-electrical resistivity, and magnetic susceptibility measurements. The gel synthesized was amorphous and highly homogeneous. Single-phase bulk samples were obtained after annealing at 1108 K for 100 h, in an atmosphere of flowing O₂ gas. XRD measurements indicated that the crystal structure remains orthorhombic (up to x=0.12 mol). With a further increase of the cadmium substitutional level, peaks of Y-124 phase disappeared. Doping the YBa₂Cu₄O₈ phase with cadmium showed a strong effect on the superconducting properties increasing the critical temperature (T _c) from 80 K (for the nonsubstituted sample) to 92 K (for the (Y_0.88Cd_0.12)Ba₂Cu₄O₈), and T _c decreases with a further increase of the cadmium substitutional level. Also prepared was a series of (Y_1?x Cd _x Ba₂Cu₄O₈) samples with (0.0≤x≤0.08 mol), via the ceramic method and annealed at 1123 K for 132 h in an atmosphere of flowing O₂ gas. The characterization of the final products was conducted by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analysis. We have not observed any trace of the superconducting Y-124 phase in any of our Cd doped samples.     

Se化Cu2ln2O5法制备CulnSe2薄膜的机理及性能研究

黄铜矿型ＣｕｌｎＳｅ２（ＣＩＳ）多晶薄膜具有优良的光伏特性。在对现有制备工艺进行了对比分析的基础上,首次采用ｓｏｌ－ｇｅｌ法制备了Ｃｕ２ｌｎ２Ｏ５（ＣＩＯ）薄膜,经Ｓｅ化获得了结构均匀、表面平整、组成接近于化学计量比的ＣＩＳ薄膜电阻率介于１０＾５～１０＾６Ω．ｃｍ之间,与国外采用其它高成本工艺制备的薄膜性能相当。基于上述实验,对Ｓｅ化ＣＩＯ法制备ＣＩＳ半导体薄膜的机理及材料的光伏性能进行了分析。     

[001]织构和非织构CVD金刚石膜的电学特性

研究了「００１」织构和非织构金刚石膜的暗电流－电压特性、电流－温度特性以及在稳定Ｘ射线辐照下的响应。结果表明「００１」织构的金刚石膜相对非织构多晶金刚石膜具有大的暗电流和Ｘ射线响应。主要由于非织构金刚石膜含有大量的晶粒间界,导致对载流子的传输产生强烈散射。在高于５００Ｋ的温度区域内,随着温度的上升「００１」织构和非强构的金刚石膜的电流都将以指数式上升,这与Ｓｉ占据金刚石格点产生１．６８ｅＶ的激活能有关。     

TiO2-V2O5纳米复合薄膜的溶胶-凝胶制备及性能研究

采用溶胶-凝胶技术,以钛酸丁脂、V2O5粉末为原材料制备了纳米结构的TiO2-V2O5复合薄膜.使用XRD、FTIR、AFM、UV-VIS-NIR分光光度计等方法研究了复合薄膜的特性.实验结果表明:复合薄膜具有纳米孔洞结构;随V2O5含量的增加,TiO2晶相由锐钛矿向金红石的转变率大大提高,从500℃时纯TiO2的0.42%增加到含30%V2O5时的80.5%;复合薄膜在紫外区域的吸收显著增强,吸收边缘发生了红移.     

Superconducting gap in Pr x Y1−x Ba2Cu4O8 and YBa2−y Sr y Cu4O8 probed by infrared phonon self-energies

We report a reflectivity study of thez-polarized TO-phonons of Pr _x Y_1?x Ba₂Cu₄O₈ and YBa_2?y Sr _y Cu₄O₈ alloys in the temperature range 10–300 K. Anomalies of the frequency and linewidth of the plane-oxygen vibration atω～300 cm^?1 due to the opening of the superconducting gap are found to occur upon crossing the superconducting transition temperatureT _c . Phonon self-energy effects are strongly dependent onT _c , providing evidence for a relative shift of the gap with respect to the energy of phonon.     

Preparation of YBa2Cu3O7 − δ Thin Films by the Self-Template Sputtering Method

Using the self-template technique, c-axis-oriented epitaxial YBa₂Cu₃O_{7 ? δ} thin films have been prepared in situ on LaAlO₃ substrate by the d.c. magnetron sputtering method. The properties of thin film dependence on the deposition conditions of the two-step self-template method have been systematically investigated. By optimizing the parameters, high-quality YBCO thin films with T _c0 ≥ 90 K, ΔT _c ≤ 1 K, R _s (77 K, 10 GHz)～500 μΩ were reproducibly obtained. The best sample grown under optimal conditions gave a low R _s of 330 μΩ at 77 K, 10 GHz, which can be used in a microwave field.