Sang-Mook Kim

Learn More
Polymer residue-free graphene nanoribbons (GNRs) of 200 nm width at 1 μm pitch were periodically generated in an area of 1 cm(2) via laser interference lithography using a chromium interlayer prior to photoresist coating. High-quality GNRs were evidenced by atomic force microscopy, micro-Raman spectroscopy, and X-ray photoelectron spectroscopy measurements.(More)
All-solution-processed transparent thin film transistors (TTFTs) are demonstrated with silver grid source/drain electrodes, which are fabricated by printing and subsequent silver nanoparticles solution coating, which allows continuous processing without using high vacuum systems. The silver grid electrode shows a reasonable transmittance in visible range,(More)
A large area (1600 mum times 800 mum) high-brightness light-emitting diode (HB LED) employing rearranged metal pads and multipassivation layers is presented. To enlarge the active layer with a smaller mesa area and improve package productivity using large bonding pads, two electrodes were used to fabricate the LED; a primary electrode was in contact with(More)
Since the pioneering work of O’Regan and Grätzel in 1991[1] numerous studies have investigated dye-sensitized solar cells (DSSCs) as an alternative next generation solar cell. This evolution has continued to progress, and solar light-to-electricity conversion efficiencies (power conversion efficiency, PCE) have now exceeded 11%, which was attained with a 12(More)
Nanopatterned aluminum nitride (NP-AlN) templates were used to enhance the light extraction efficiency of the light-emitting diodes (LEDs). Here, the NP-AlN interlayer between the sapphire substrate and GaN-based LED was used as an effective light outcoupling layer at the direction of bottom side and as a buffer layer for growth of GaN LEDs. The(More)
White light-emitting diode (LED) packages are generally comprised of pre-mold leadframe, chip, wire, phosphor and encapsulant. During the high junction temperature operation, the whitening phenomena sometimes happen between leadframe sidewall and encapsulant resin. The nontrivial decrease of luminous flux results from the whitening originated from the(More)
Transparent electrically conducting thin films are particularly attractive and are receiving increased interest in applications such as liquid crystal displays, transparent electrodes for solar cells, and light-emitting diodes(LED). In particular, Indium tin oxide (ITO) films have been studied in view of the practical performance of their electrical and(More)
Nanosphere lithography is proposed as a new technique for the fabrication of nanoscale pillars on p-GaN layer. This technique is an easy and simple process using a self-assembled monolayer of spheres, which act as etching masks to form pillars on a Si3N4 substrate, that could be utilized as a stamp for UV-based imprint lithography. We can apply the UV-based(More)
To reduce the variance of color temperature among packages and the spatial color temperature variance in the package, we adopted a unique phosphor conformal coating technique in the packaging process, thereby fabricating the self-positioned phosphor layer. Additionally, to acquire the spatial color uniformity without considerable shrinkage of luminous(More)
We textured the surface of a silicone encapsulant to increase the extraction efficiency of white light-emitting diodes (LEDs) by using a plasma treatment. Here, the surface morphology could be controlled by changing the plasma condition and texturing morphology of the silicone encapsulant were proportion to the increased ratio of white LEDs. The luminous(More)