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Publications (4)1.04 Total impact

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    ABSTRACT: Good bonding of single-crystal semiconductor thin-film (epifilm) on diamond-like carbon (DLC) thin film formed on the Si substrate (DLC/Si) by intermolecular force at room temperature has been achieved for the first time. Characteristics of super high-density epifilm-LED arrays bonded on DLC/Si are compared with those bonded on polyimide film on the Si substrate (PI/Si). Performance test showed much larger emitted-light-power efficiencies on DLC/Si than those on PI/Si in the larger current-density range. The current-power characteristic curve of the epifilm-LED bonded on DLC/Si was found to saturate at much larger LED-current compared to conventional LEDs on the GaAs substrate. The epifilm-LED on DLC/Si achieved much larger heat-dissipation and higher emitted-light-powers at larger LED-currents.
    Electron Devices Meeting, 2008. IEDM 2008. IEEE International; 01/2009
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    ABSTRACT: Bonding of single crystal thin film ("epifilm") by intermolecular-force ("epifilm bonding" (EFB)) has been investigated from view point of high-density integration of LEDs on dissimilar material substrates. Several bonding layers having different surface-roughness (Rpv) have been tested. Test result showed that EFB state on the bonding layer with Rpv~1nm was much better than those on bonding layers with Rpv >> 1nm; smooth surface of Rpv~1nm is preferable to achieve good EFB state. Diamond-like carbon (DLC) thin film with Rpv~1nm by chemical-vapor-deposition has been also tested as the bonding layer. Good EFB state on the DLC thin film has been achieved by optimizing of surface activation of the DLC thin film. EFB on the DLC thin film having higher thermal conductivities will be promising for high-density device-integration to obtain higher heat-dissipation and better device performance.
    ECS Transactions 10/2008; 16(8).
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    ABSTRACT: Higher density single crystal thin film light emitting diode (LED) arrays have been studied. Bonding of epitaxial thin film (epifilm) LEDs of about 2 mum in thickness has been achieved on CMOS IC drivers and other dissimilar material substrates by intermolecular force ("Epi Film Bonding (EFB)" technology). The epifilm LED array provides good enough characteristics to apply in LED printheads (small variation of emitted light power (< plusmn 5%) and long lifetime (>1000 h)). Fabrication test of two dimensional (2D) epifilm LED arrays shows that 2D 1200 dpi epifilm LED arrays (a small light emitting region of 10 mum times 10 mum and a fine array pitch of 21.2 mum) achieves good performance to display characters. Bonding of 1200 dpi epifilm LED arrays on diamond-like carbon (DLC) thin films having high thermal conductivity has been tested for the first time. The test result shows that good bonding of small epifilms (10 mum times 10 mum) on the DLC thin film can be achieved. The LED array that is bonded on the DLC thin film formed on the Si substrate shows higher thermal conduction character; rough estimation of LED temperature suggests about 50 degrees centigrade even at a very high LED current density of 20 kA/cm<sup>2</sup>.
    Electronic Components and Technology Conference, 2008. ECTC 2008. 58th; 06/2008
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    ABSTRACT: A 600 dots per inch LED array chip integrated with Si drivers using a three-dimensional epitaxial thin-film bonding has been developed. Performance tests showed high emitted light power (47 μW at an LED current of 1 mA) with smaller variations (±7%), and long lifetime. Test results provide good enough characteristics to use the LED array chip in a high-printing-speed LED printer printhead.
    Electronics Letters 08/2006; · 1.04 Impact Factor