Mr. Kyoung Hoon Kim Profile

Mr. Kyoung Hoon Kim

Graduate Student at Kansas State Univ

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Publications (5)

PROCEEDINGS ARTICLE | October 20, 2004

Mg-doped Al-rich AlGaN alloys for deep UV emitters

Proc. SPIE. 5530, Fourth International Conference on Solid State Lighting

KEYWORDS: Light emitting diodes, Magnesium, Deep ultraviolet, Doping, Aluminum, Aluminum nitride, Metalorganic chemical vapor deposition, Gallium, Crystal optics, Temperature metrology

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PROCEEDINGS ARTICLE | October 20, 2004

III-nitride blue and UV photonic-crystal light-emitting diodes

Proc. SPIE. 5530, Fourth International Conference on Solid State Lighting

KEYWORDS: Light emitting diodes, Ultraviolet radiation, Photonic crystals, Electroluminescence, Ultraviolet light emitting diodes, Near field scanning optical microscopy, Optical pumping, Gallium, Near field optics, Blue light emitting diodes

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PROCEEDINGS ARTICLE | June 16, 2004

Subpicosecond Raman studies of nonequilibrium electron transport in an In0.4Ga0.6N epilayer grown on GaN

Proc. SPIE. 5352, Ultrafast Phenomena in Semiconductors and Nanostructure Materials VIII

KEYWORDS: Semiconductors, Surface plasmons, Scattering, Luminescence, Raman spectroscopy, Gallium nitride, Monte Carlo methods, Raman scattering, Electron transport, Indium nitride

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PROCEEDINGS ARTICLE | June 11, 2002

Time-resolved photoluminescence studies of Al-rich AlGaN alloys

Proc. SPIE. 4643, Ultrafast Phenomena in Semiconductors VI

KEYWORDS: Magnesium, Luminescence, Silicon, Doping, Gallium nitride, Aluminum, Excitons, Metalorganic chemical vapor deposition, Gallium, Temperature metrology

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Si-doped n-type Al_xGa_1MINxN alloys with x up to 0.5 and Mg-doped p-type Al_xGa_1-xN alloys with x up to 0.27 were grown by metal-organic chemical vapor deposition (MOCVD) on sapphire substrates. For the n-type Al_xGa_1-xN, we achieved highly conductive alloys for x up to 0.5. An electron concentration as high as 1x10¹⁸cm^-3 was obtained in Si-doped Al_0.5Ga_0.5N alloys with an electron mobility of 16 cm$_2)Vs at room temperature, as confirmed by Hall-effect measurements. Our results also revealed that the conductivity of Al_xGa_1-xN alloys continuously increases with an increase of Si doping level for a fixed value of Al content (X<0.5), the conductivities of Al_xGa_1-xN alloys decrease with increasing Al content for a given doping level; the critical Si-doping concentration needed to convert insulating Al_xGa$1-x)N with high Al contents (X>=0.4) to n- type conductivity is about 1 x 10¹⁸cm^-3. Time- resolved photoluminescence studies carried out on these materials have shown that Si-doping reduces the effect of carrier localization in Al_xGa_1-xN alloys and a sharp drop in carrier localization energy occurs when the Si doping concentration increases above 1x10¹⁸cm^-3, which directly correlates with the observed electrical properties. For the Mg-doped Al_xGa_1-xN alloys, p-type conduction was achieved for x up to 0.27, as confirmed by variable temperature Hall measurements. Emission lines of band-to-impurity transitions of free electrons with neutral Mg acceptors as well as localized excitons have been observed in the p-type Al_xGa_1-xN alloys. The Mg acceptor activation energies E_A were deduces from photoluminescence spectra and were found to increase with Al content and agreed very well with those obtained by Hall measurements. From the measured activation energy as a function of Al content, E_A versus x, the resistivity of Mg-doped Al_xGa_1-x with high Al contents can be deduced. Our results have also shown that PL measurements provide direct means of obtaining E_A especially where this cannot be obtained accurately by electrical methods due to high resistance of p-type Al_xGa_1-xN with high Al content.

PROCEEDINGS ARTICLE | April 23, 2001

Growth and optoelectronic properties of III-nitride quaternary alloys

Proc. SPIE. 4280, Ultrafast Phenomena in Semiconductors V

KEYWORDS: Sensors, Ultraviolet radiation, Quantum efficiency, Atomic force microscopy, Gallium nitride, Optoelectronics, Aluminum, Indium gallium nitride, Heterojunctions, Ultraviolet detectors

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