Hui-Youn Shin

Low-temperature growth and direct transfer of graphene–graphitic carbon films on flexible plastic substrates

We demonstrate low-temperature growth and direct transfer of graphene-graphitic carbon films (G-GC) onto plastic substrates without the use of supporting materials. In this approach, G-GC films were synthesized on copper layers by using inductively coupled plasma enhanced chemical vapor deposition, enabling the growth of few-layer graphene (G) on top of Cu and the additional growth of graphitic carbon (GC) films above the graphene layer at temperatures as low as 300 °C. The patterned G-GC films are not easily damaged or detached from the polymer substrates during the wet etching and transfer process because of the van der Waals forces and π-π interactions between the films and the substrates. Raman spectroscopy reveals the two-dimensional hexagonal lattice of carbon atoms and the crystallinity of the G-GC films. The optical transparency and sheet resistance of the G-GC films are controlled by modulating the film thickness. Strain sensors are successfully fabricated on plastic substrates, and their resistance modulation at different strains is investigated.

Structural characterization of CdSe/ZnS core–shell quantum dots (QDs) using TEM/STEM observation

CdSe/ZnS core–shell structured nano-crystal quantum dots (QDs) are ideal candidates for light-emission applications due to their high quantum efficiency, narrow-band, and particle-size-tunable photoluminescence. In particular, their small size results in the quantum confinement of semiconductor nano-crystals, which widens their energy gaps. In general, structural analyses of QDs using a transmission electron microscope (TEM) are very important due to the significantly small size of QDs. We were able to obtain structural information of CdSe/ZnS core–shell QDs using nano-beam diffraction by controlling the nano-probe of the dark field scanning TEM (DF-STEM) mode and strain analysis with high-resolution TEM (HRTEM)/STEM images. Furthermore, we could clearly distinguish the interface between the CdSe core and the ZnS shell from the strain analysis with the HRTEM/STEM images.

LP‐G: Late‐News Poster: Hybrid Switching Mode for Wide‐Viewing‐Angle TFT‐LCDs

This paper reports on a hybrid switching(HS) mode for achieving wide viewing angle TFT-LCDs. In the newly developed HS mode, pixel electrodes are designed to apply electric field both in the vertical and horizontal direction, which is effective for high display performance as well as wide viewing angle. We have developed high performance 14.1 inch TFT-LCD monitor using HS method.

Effect of oxygen incorporation in a-plane GaN on p-type ohmic contact property

We report on the origin of the non-ohmic behavior of Ni/Au-based p-type contacts on a nonpolar a-plane GaN layer. The contact properties of Ga-polar c-plane GaN and nonpolar a-plane GaN are compared. While the Ga-polar c-plane shows ohmic-contact properties in the Ni/Au contact after heat treatment, the nonpolar a-plane shows rectifying characteristics both before and after heat treatment. We determined the reasons why the two planes show substantial differences in contact properties using various tools. We conclude that the differences originated from the oxygen incorporation preference resulting in gallium oxide formation at the interface of nonpolar a-plane GaN.