Hyong-Jun Kim

Effectiveness of p-dopants in an organic hole transporting material

We investigated the effectiveness of p-dopants to generate holes in a hole transporting material by comparing the absorption in visible-near-infrared and infrared regions and current density-voltage characteristics. CuI, MoO3, and ReO3 having different work functions were doped in a hole transporting organic material, 4,4′,4″-tris(N-(2-naphthyl)-N-phenylamino)-triphenylamine (2TNATA). Formation of charge transfer (CT) complexes increases linearly with increasing doping concentration for all the dopants. Dopants with higher work function (ReO3>MoO3>CuI) are more effective in the formation of CT complexes and in the generation of the charges in the doped films.

Formation of flat, relaxed Si1−xGex alloys on Si(001) without buffer layers

Atomically flat, fully strained Si1−xGex layers with thicknesses ranging from 40 to 240nm were grown on Si(001) at 450°C by ultrahigh-vacuum chemical vapor deposition and subjected to annealing at 1000°C for 20min to induce relaxation. In order to minimize surface diffusion during annealing and thereby inhibit strain-induced roughening in favor of misfit dislocation formation, SiO2 capping layers are deposited prior to annealing. The overall process results in smooth, relaxed alloy layers without the necessity of using several-μm-thick compositionally graded buffer layers.

Si(011)16×2 gas-source molecular beam epitaxy: Growth kinetics

The growth rates RSi of Si layers deposited on Si(011)“16×2” by gas-source molecular beam epitaxy from Si2H6 were determined as a function of temperature Ts (400–975 °C) and Si2H6 flux JSi2H6(5.0×1015–9.0×1016 cm−2 s−1). RSi ranges from 0.0015 μm h−1 at Ts=400 °C to 0.415 μm  h−1 at Ts=975 °C with JSi2H6=2.2×1016 cm−2 s−1. In the surface-reaction-limited regime at Ts 900 °C, RSi(Ts) increases with Ts due to surface roughening. Overall, RSi(JSi2H6,Ts) is well described at Ts⩽900 °C by a kinetic model incorporating two competing film growth mechanisms: (1) dissociative chemisorption of Si2H6 onto dangling bonds followed by fast surface dissociation steps and second-order H2 desorption from the surface monohydride phase; and ...

Cloning and sequence analysis of the Δ1-pyrroline-5-carboxylate synthase gene (MP5CS) from mulberry (Morus alba) and patterns of MP5CS gene expression under abiotic stress conditions

ABSTRACT Drought is an important plant growth-limiting factor. ∆1-Pyrroline-5-carboxylate synthase (P5CS) is a key enzyme closely related to proline biosynthesis under drought stress. A full-length cDNA sequence from the P5CS gene in mulberry (Morus alba), designated MP5CS (GenBank Accession Number KC202259), was cloned. MP5CS was 2190 bp in length, contained a 47-bp 5ʹ-untranslated region (5ʹ-UTR) and a 648-bp 3ʹ-UTR, and encoded 497 amino acids with a predicted molecular weight of 53.92 kDa and an isoelectric point of 9.35. Phylogenetic analysis based on P5CS gene sequences from various species showed that mulberry was closely related to Boehmeria nivea, Malus hupehensis, Gossypium arboreum, and Euonymus japonicas. MP5CS gene expression under drought or salt stress conditions was quantified by quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR). The results showed that both abiotic stresses caused a significant upregulation in the expression of MP5CS in leaves compared to a normal growth environment. These data provide a better understanding of the molecular basis of signal transduction during stress responses in mulberry trees.

P-161: Effectiveness of p-Dopants in an Organic Hole Transporting Material

We investigated the effectiveness of p-dopants such as CuI, MoO3 and ReO3 having different work functions to generate holes in a hole transporting material of 4,4′,4″-tris(N-(2-naphthyl)-N-phenyl-amino)-triphenylamine (2TNATA). Dopants with larger work function (ReO3>MoO3>CuI) are more effective in the formation of CT complexes and in the generation of the charges.

Fluorescent Nano-Assembly of Organic Conjugate Molecules with Benzoxazole Moiety and Its Application in Sensor

Fluorescence labeling or sensing is a very useful analytical technique for investigating the structure of living cells or for detecting ionic metals. Numerous materials including inorganic quantum dots and organic fluorescent dyes have been used and investigated for further development so far. However, they are inherited natural discrepancies of cyto-toxicity or easy degradation. Thus, developing highly emissive, biocompatible, and chemically readily modifiable luminescent materials is strongly desired. Here, we report the enhanced photoluminescence of an oxazole derivative for possible use in the field of fluorescent sensor.

Effect of C Incorporation on the Growth Kinetics of Si 1-x- y Ge x C y Layers

In this article, SiGeC layers were grown on Si by ultra-high vacuum CVD (UHVCVD) and the growth kinetics of SiGeC layer were investigated by varying methylsilane flow rate and growth temperature. We investigated the incorporation behavior of C and observed the two-step growth kinetics due to strong C-H bonds and non-substitutional C incorporation