Bo-Soon Kim

Enhancement of electroluminescence in GaN-based light-emitting diodes by metallic nanoparticles

The enhanced electroluminescence of GaN-based light-emitting diodes (LEDs) with noble metallic nanoparticles (MNPs) is demonstrated. The sample with well-designed Ag MNPs has shown the best performance enhancement of 126% in electroluminescent intensity compared with a conventional LED sample, even though the MNPs are placed at least 200 nm away from the quantum-well active layer. The MNPs provide enhanced photon scattering and coupling between localized surface plasmon resonance (LSPR) modes and photon modes internally trapped in a device. To investigate this effect, the peculiarities of the LSPR and the corresponding structural properties of the MNPs are discussed through the effective medium approach.

Residual Layer Distribution on Embossing Process for Photonic Devices

We report on the behavior and effect of the residual layer left on the substrate after embossing process for the fabrication of photonic devices. The PDMS material was used as mold, and thermal and UV curable polymers was adapted for the fabrication of demultiplexer and optical power splitter, respectively.

Fabrication of polymer AWG demultiplexer using embossing technique

We fabricated an arrayed waveguide grating (AWG) demultiplexer for optical fiber communication systems and photonic integrated circuits. We also used an embossing technique to fabricated the AWG instead of traditional semiconductor technologies, such as photolithography and etch process. UV curable polymers (ZPU 12-47 and ZPU 12- 45) were used as the core and upper cladding layers. The polydimethylsiloxane (PDMS) mold used for the embossing process is manufactured by a photoresist structure formed on a silicon wafer. We tried the embossing onto a fused silica glass using the PDMS mold. After UV curing, the PDMS mold was peeled away carefully, and a pattern of the AWG demultiplexer was left on the surface of that substrate. The upper cladding layer was coated over the patterned structure. The fabrication of the AWG demultiplexer was completed by a cleaving process. The residual layer produced after an embossing process was adjusted by the volume of polymer droplet. The embossing technique will have the potential for broad applications in fabrication of photonic devices.