氧化物薄膜製作及電性測量

Indium oxide doped with tin oxide, ITO, is used to make transparent conductive coatings. Thin film layers can be deposited by electron-beam evaporation or sputtering. Typical applications of ITO-coated substrates include touch panel contacts, electrodes for LCD and electrochromic displays, energy conserving architectural windows, defogging aircraft and automobile windows, heat-reflecting coatings to increase light bulb efficiency, gas sensors, antistatic window coatings, wear resistant layers on glass, etc.

實驗有缺失: 暑假當義工, 進一步加強 實驗物理與技術的訓練

暑假提供實驗物理專題研究機會: 奈米, 生物磁學, 薄膜光電, 元件特性, 磁共振造影術, SQUID 應用 請與助教討論, 提出實驗構想與方案

Film Properties High conductivity (or low sheet resistance) is balanced against high transmission in the visible region. Sheet resistance can be less than 10 Ohms/sq. with a visible transmission of >80%. To obtain transmission near 90%, sheet resistance must be >100 Ohms/sq. ITO films behave as metals to long wavelength light because of the presence of a plasma wavelength above 1 µm. At longer wavelengths, the film becomes reflecting, and the IR reflectance is related to the sheet resistance of the film; sheet resistance must be <30 Ohms/sq. to obtain IR reflectance >80%.

Physical Properties of Solid ITO Material Molecular Weight Varies with composition Melting Point~1900° C Color Light yellow to gray, depending on degree of oxidation Crystal Density~7.14 g/cc

Schematic diagram of the rf sputtering system used in this work ITO Nd0.7Sr0.3MnO3 PrBa2Cu3Oy Ar+O2 gas YBa2Cu3Oy 5.3 cm 3.5 cm 3 cm shutter rf sputtering gun sample holder water-cooled stainless-steel shielding L. M. Wang, H. W. Yu, H. C. Yang and H. E. Horng, Physica C, 256, 57 (1996).

Sputtered Film Applications The high oxide composition of high density target and bulk ITO forms make them ideal for low temperature applications, such as polymer substrates for LCD, touch panels, and other high volume production needs.

OUTLINE Introduction Experiments Growth of superlattices Transport Properties Results and Discussion -2 X-diffraction pattern Hall coefficients Flux pinning Dimensinality Conclusion

RMMO is ferromagnetic, whereas PBCO is insulating at low temperatures. In this work , we investigated the flux pinning, the mixed state Hall coefficients, the superconductivity and magnetoresistance of YBCO/RMMO multilayers. The results are compared with that of YBa2Cu3Oy/PrBa2Cu3Oy (YBCO/PBCO) superlattices. YBCO/RMMO: YBa2Cu3Oy/R0.7M0.3MnO3 with R = La or Nd and M = Ca and Sr YBCO/PBCO : YBa2Cu3Oy/PrBa2Cu3Oy R RMMO is ferromagnetic, whereas PBCO is insulating at low temperatures.

Sample preparation The superlattices were prepared by the rf magnetron sputtering method.

Crystal Structure of YBa2Cu3Oy (YBCO) and La0.7Ca0.3MnO3 (LCMO):

1m Surface morphology of an as grown YBCO film with root mean square roughness of about 8.2 Å

● AFM image La0.7Ca0.3MnOy Scanned area = 30m30m; RMS roughness = 8.4 Å

2D sinθ= λ D = /2(sinn+1 - sinn) ● X-ray diffraction 2d sinθ= λ θ d LCMO YBCO STO 2D sinθ= λ D = /2(sinn+1 - sinn) Satellite peak *

-2 X-diffraction pattern

-2 x-ray diffraction pattern of a (YBa2Cu3Oy/PrBa2Cu3Oy) (96 Å/60 Å)10 superlattice.

磁化量 M 的測量

NSMO and LCMO films show the Curie temperature at 222 K and 250 K respectively.

Transport Measurements in magnetic fields Hall measurements Resistivity Hall measurements

● The pattern for resistivity and Hall measurements V = V3-V2→Resistance Vh = V2-V1→Hall coefficient

xx in magnetic fields parallel to (a) the c-axis (b) the ab-plane.