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Gwangju, South Korea

Mun D.-H.,Chonnam National University | Bak S.J.,Chonnam National University | Ha J.-S.,Chonnam National University | Lee H.-J.,Dong - A University | And 3 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2014

In this study, we grew ZnO nanowires hydrothermally on (1-102) r-plane sapphire substrates in an aqueous solution which contained zinc nitrate hexahydrate and hexamethylenetetramine (HMT) at 90 °C. First, the AZO seed layer of 80 nm thickness was deposited on the r-plane sapphire substrate by a radio frequency magnetron sputter. After that, we grew the ZnO nanowires on the seed layer by changing the precursor concentration of the aqueous solution from 0.025 M to 0.01 M. When the molar concentration of the precursor was changed, the diameter, length, density and number of ZnO nanowires also changed significantly: diameter, length and density increased with increasing molar concentration but the number of ZnO nanowires decreased. The ZnO nanowires grown at the higher molar concentration tended to grow along with the c-axis direction, as revealed by atomic force microscope and X-ray diffraction peaks. Furthermore, the PL spectra measured at room-temperature revealed a UV emission of 380 nm which can be attributed to the radiative recombination of free and bound excitons (Near Band edge Emission). The NBE emission was also increased with increasing molar concentration. Copyright © 2014 American Scientific Publishers. Source

Zhao J.L.,Tianjin University | Sun X.W.,Tianjin University | Sun X.W.,Nanyang Technological University | Ryu H.,Inje University | Moon Y.B.,THELEDS Co.
Optical Materials | Year: 2011

Highly transparent conductive Ga-doped ZnO (GZO) thin films have been prepared on glass substrates by metal organic chemical vapor deposition. The effect of Ga doping on the structural, electrical and optical properties of GZO films has been systematically investigated. Under the optimum Ga doping concentration (∼4.9 at.%), c-axis textured GZO film with the lowest resistivity of 3.6 × 10-4 Ω cm and high visible transmittance of 90% has been achieved. The film also exhibits low transmittance (<1% at 2500 nm) and high reflectance (>70% at 2500 nm) to the infrared radiation. Furthermore, our developed GZO thin film can well retain the highly transparent conductive performance in oxidation ambient at elevated temperature (up to 500 °C). © 2010 Elsevier B.V. All rights reserved. Source

Theleds Co. | Date: 2010-10-20

Provided is a light emitting diode package. The light emitting diode package includes a package body, a light emitting diode chip, and a package lens. The light emitting diode chip is installed in the package body. The package lens is installed in the package body to cover the light emitting diode chip, and is formed to have a shape corresponding to a radiation angle pattern of the light emitting diode chip.

Theleds Co. | Date: 2011-01-13

Provided is a semiconductor light emitting device having an improved electrode structure for uniform current density and high brightness. According to the present invention, an light emitting device can have an electrode structure configured to spread a current uniformly and efficiently throughout the entire area of the light emitting device. Therefore, current density distribution can be more uniform in the light emitting device. End parts of second conductive type auxiliary electrodes are gradually shortened in length in a direction away from a first conductive type electrode pad so that a current flowing around the first conductive type electrode can be uniform to increase optical conversion efficiency and lower a driving voltage.

There are provided a semiconductor substrate configured to improve the light extraction efficiency of a light emitting device, and a light emitting device using the substrate. The light emitting device includes the substrate, a buffer layer, and a light emitting structure, and the buffer layer and the light emitting structure being sequentially stacked on the substrate. The substrate includes a plurality of lenses disposed on a top surface thereof, and the lenses have a horn shape and are configured such that the buffer layer grows both on the top surface of the substrate and lateral surfaces of the lenses.

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