Browsing by Author "Tsai, RY"

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Atomic force microscope study of GaN films grown by hydride vapor phase epitaxy
(1999)
Fang, HM
;
Wang, YK
;
Tsai, RY
;
Chu, CF
;
Wang, SC
We report the results of the investigation of the structural, surface morphological, and optical properties of GaN films grown by hydride vapor phase epitaxy. These films were grown on sapphire substrate with no intentional dopings. These as-grown GaN film samples with thickness ranging from 5.58 mu m to 14.9 mu m were investigated under room temperature conditions. The surface morphology of these films was investigated using an atomic force microscopy (AFM). The root mean square (RMS) values of surface roughness range from 0.281 nm to 0.133 nm. The thicker films show lower defect counts with a defect density of about 2 x 10(8) cm(-2). The structural property of these films was measured by double crystal X-ray diffraction (DC-XRD). The full width at half maximum (FWHM) of X-ray diffraction angle decreases as the film thickness increases with a lowest FWHM of about 265.5 arcsec. The optical properties of these films were investigated by photoluminescence (PL) measurement at room temperature. The results show a dominant near band-edge UV emission peak that increases with the film thickness with very weak yellow emission band.
New fabrication for DSRRs nanostructure in optics
(2006-01-01)
Chu, CS
;
Tsai, RY
;
Lai, P
;
Chern, JL
;
光電工程學系
The Deformed-Split-Ring Resonators (DSRRs) require metal nanostructure on high transmission material substrate for optical application. In this article, a simple method of fabricating three-dimensional polymer nanostructure that use an UV-curable polymer as the resist is discussed. Because UV cure imprinting has high resolution which is about 100nm and high transparency, it is ideally suited for photonic and meta-material optical device applications. The fabrication combines several mass production technologies. The first one is photolithography, such as a stepper UV exposure system can make the nano scale pattern in photoresist, the second is to change the photoresist sample to become the nanoimprint mould by precise electroforming, the third is to use UV cure imprinting to transfer the DSRRs pattern on the UV-curable polymer. Finally, it is also the most important process is that to coat metals and metal lift-off that coating Ag to become buffer layer by sputter, then coating Au into the nanostructure and lift off Ag by HNO3. The DSRR structure is implemented in high transmission UV-curable polymer with Au.