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We demonstrate that a filtration method is efficient for the fabrication of thick single-walled nanotube films and is capable of shielding terahertz waves. Shielding effectiveness can be engineered by controlling the film thickness and we achieved 38 dB for a 950-nm-thick film. In addition, we found that the films exhibit a dispersion of dielectric constant obeying the Drude free-electron model, whereas the plasma frequency decreases with increasing film thickness. Based on the nanotube films with a thickness greater than the skin depth, we fabricated grid polarizers by laser-machining process, which enable us to achieve a large polarization extinction ratio. [ABSTRACT FROM AUTHOR]

We studied the role of a patterned SiO2 current-blocking layer (CBL) on the output power in polycrystal n-type ZnO:Ga/p-Si heterojunction light emitting diodes (LEDs). The introduction of a CBL considerably improved the light extraction efficiency by about 200%, despite the increased series resistance. It suppressed the vertical current with a low extraction efficiency by opaque metals and allowed the spreading current component to be enhanced, in contrast to conventional n-ZnO/p-Si LEDs operated only a vertical current component due to the grain boundaries in the ZnO films. This result suggests that the use of CBL is profitable method in the emitter application using the film with the polycrystal structure. [ABSTRACT FROM AUTHOR]