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Yanggu, South Korea

Kim J.Y.,Sunchon National University | Kim J.Y.,LumiGNtech Co | Kim J.-K.,Sunchon National University | Kim J.-Y.,Korea Photonics Technology Institute | And 3 more authors.
Thin Solid Films | Year: 2013

Ag-embedded indium tin oxide (ITO) films were deposited on Corning 1737 glass by radio-frequency magnetron sputtering under an Ar or Ar/O2 mixed gas ambient with a combination of ITO and Ag targets that were sputtered alternately by switching on and off the shutter of the sputter gun. The effects of a subsequent surface treatment using H2 and H2 + O 2 mixed gas plasma were also examined. The specific resistance of the as-deposited Ag-embedded ITO sample was lower than that of normal ITO. The transmittance was quenched when Ag was incorporated in ITO. To enhance the specific resistance of Ag-embedded ITO, a surface treatment was conducted using H2 or H2 + O2 mixed gas plasma. Although all samples showed improved specific resistance after the H2 plasma treatment, the transmittance was quenched due to the formation of agglomerated metals on the surface. The specific resistance of the film was improved without any deterioration of the transmittance after a H2 + O2 mixed gas plasma treatment. © 2013 Elsevier B.V.


Kim J.Y.,Sunchon National University | Kim J.Y.,LumiGNtech Co | Lee D.-M.,Sunchon National University | Kim J.-K.,Sunchon National University | And 2 more authors.
Applied Surface Science | Year: 2013

This study examined the effects of H2 and H2 + O 2 mixed gas plasma treatment on the properties of ITO films. The films were deposited on corning glass by RF magnetron sputtering under Ar and Ar/O2 mixed gas ambient. After a H2 plasma treatment, the ITO films showed an improved specific resistance due to the formation of oxygen vacancies acting as shallow donors, but showed quenched transmittance due to the formation of agglomerated metals on the surface. After an H2 + O2 mixed gas plasma treatment, the specific resistance of the film was improved without deteriorating transmittance. The enhanced specific resistance by mixed gas plasma treatment was attributed to the formation of free electrons by the incorporation of H in the lattice. © 2012 Elsevier B.V. All rights reserved.


Provided are a semiconductor substrate including an uneven structure disposed on a surface of a substrate, a buffer layer disposed on the uneven structure, the buffer layer having an acicular structure, a compound semiconductor layer disposed on the buffer layer to planarize the uneven structure, and a plurality of voids defined between the substrate and the compound semiconductor layer, and a method for manufacturing the same. Thus, since the acicular structure disposed on the uneven structure of the substrate forms the voids on an interface between the substrate and the single crystal GaN layer to relax a stress due to a lattice mismatch and intercept propagation of a breakdown potential, a warpage characteristic of the grown single crystal GaN layer may be reduced, as well as, crystallinity may be improved.


Wang J.,Dong - Eui University | Ryu H.-B.,Dong - Eui University | Park M.-S.,Dong - Eui University | Lee W.-J.,Dong - Eui University | And 2 more authors.
Journal of Crystal Growth | Year: 2013

GaN epilayers were grown on Si(111) at 980 °C by a hydride vapor phase epitaxy (HVPE) method. AlxGa1-xN with thickness of ∼900 nm was inserted between Si substrate and GaN epilayer to act as a buffer layer. The investigation of the influence of different V/III ratios on GaN epilayer qualities reveals that high GaCl flow rate can increase the growth rate and improve the surface morphologies of GaN epilayers while high NH 3 flow rate is not good for reducing dislocations in GaN epilayers, which can be proved from the analysis of X-ray diffraction rocking curve (XRC), cross-sectional image of scanning electron microscopy (SEM) and image of atomic force microscopy (AFM). Finally, 1.22 μm GaN epilayer without cracks was successfully obtained with a three-step growth method. The surface roughness average (Ra) was measured to be 1.45 nm and the FWHM of GaN(0002) was 599 arcsec. The measured lattice constants for GaN epilayer were a=3.210 Å and c=5.177 Å, indicating the in-plane tensile stress and out-of-plane compressive stress of GaN epilayer. © 2012 Elsevier B.V. All rights reserved.


Ha J.-H.,Dong - Eui University | Wang J.,Dong - Eui University | Lee W.-J.,Dong - Eui University | Choi Y.-J.,LumiGNtech Co | And 3 more authors.
Journal of the Korean Physical Society | Year: 2015

The hydride vapor-phase epitaxy (HVPE) method was used to deposit high-quality InN layers on GaN inter-layer/sapphire (0001) structures that had been fabricated by using either the HVPE method or the metal-organic chemical-phase deposition (MOCVD) method. The effects of the group V/III ratio and different GaN inter-layers on the crystal quality of the InN layers were systemically investigated. The InN layer grown at a low Group V/III ratio revealed a high crystal quality with a two-dimensional (2D) growth mode. Also, the 110.7-nm-thick InN layer grown by using HVPE on a GaN inter-layer/sapphire (0001) substrate structure that had been fabricated by using MOCVD had a high crystal quality, with the full width at half maximum (FWHM) of the InN X-ray diffraction (XRD) peak being about 844 arcsec, and a smooth surface with an atomic force microscopy (AFM) roughness of about 0.07 nm. On the other hand, the 145.7-nm-thick InN layer grown by using HVPE on a GaN inter-layer/sapphire (0001) substrate structure that had been fabricated by using the HVPE method had a lower crystal quality, a FWHM value for the InN (0002) peak of about 2772 arcsec, and a surface roughness of about 3.73 nm. In addition, the peak of the E2 (high) phonon mode for the 110.7-nm-thick InN layer grown by using HVPE on a GaN inter-layer/sapphire (0001) structure that had been fabricated by using MOCVD was detected at 491 cm -1 and had a FWHM of 9.9 cm-1. As a result, InN layers grown by using HVPE on GaN inter-layer/sapphire (0001) substrate structures fabricated by using MOCVD have a high crystal quality and a reduced Raman value, which agrees well with the results of the XRD analysis. © 2015, The Korean Physical Society.

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