Hyun-Wook Ryu

Growth and Surface Morphology of Textured NiO Thin Films Deposited by Off-Axis RF Magnetron Sputtering

Textured crystalline NiO thin films were grown on Si(100) substrates by off-axis RF magnetron sputtering without substrate heating using a NiO target. (100)-textured NiO films were obtained using pure Ar gas. On the other hand, (111)-textured NiO films were obtained using pure O2 gas. Also, the surface morphology and roughness of the NiO thin films were closely related to the type of sputtering gas and RF power.

X-RAY DIFFRACTION STUDIES OF EPITAXIAL LA0.5SR0.5COO3 THIN FILMS PREPARED BY THE DIPPING-PYROLYSIS PROCESS

A reciprocal-space map (ω–2θ scans) can provide more information than conventional X-ray diffraction (XRD) θ–2θ scans. In this study, an epitaxial La0.5Sr0.5CoO3 thin film prepared on the SrTiO3(100) substrate by the dipping-pyrolysis (DP) process was investigated based on XRD θ–2θ scanning, β scanning (pole figure) and asymmetric ω–2θ scanning. An epitaxial La0.5Sr0.5CoO3 film annealed at 800°C was found to consist of the pseudocubic phase with a d∥/d⊥ ratio of 1.005 by reciprocal-space map analysis.

Crystallinity and surface morphology of chemical solution derived epitaxial Bi4Ti3O12 thin films on (100)LaAlO3

Bi4Ti3O12 thin films were prepared on single-crystal (100)LaAlO3 substrates by chemical solution deposition using metal naphthenates as starting materials. Precursor films were pyrolyzed at 500°C for 10 min in air and finally annealed at 650, 700, 750 and 800°C for 30 min in air, followed by rapid cooling. Crystallinity and in-plane alignment of the thin films were investigated by X-ray diffraction θ–2θ scans and pole-figure analysis. A field emission-scanning electron microscope and an atomic force microscope were adopted for characterizing the surface morphology and the surface roughness of the films. Epitaxially grown thin films annealed at 650 and 700°C exhibited extremely flat surfaces. On the contrary, with the increase in annealing temperatures to 750 and 800°C, the columnar grain size and width of the films uniformly increased.

Auxin treatment improves indigo biosynthesis in hairy root cultures of Polygonum tinctorium

305-754, Korea, fax 82 42 822 2631, e-mail: supark@cnu.ac.kr; 2) SENOCO Co. 322-1 Dongsoo-Dong, Naju, Chonnam, 520714, Korea, Fax 82 61 336 8919, e-mail: senoco@naver.com; 3) School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Korea, fax 82 62 53

Hillock Formation of SnO2 Thin Films Prepared by Metal-Organic Chemical Vapor Deposition

SnO2 thin films were deposited at 375°C on an alumina substrate by metal-organic chemical vapor deposition (MOCVD). The number of hillocks on the thin-film surface increased with air annealing. The oxygen content and binding energy during air annealing at 500°C came close to those of stoichiometric SnO2. The cauliflower-like hillocks observed seem to be the result of the continuous migration of tiny grains to release the stress of an expanded grain.