[Design & fabrication of nanostructures]
A main research goal at NDDL is designing and fabricating various nanostructures. We are focusing on designing nanostructures using various simulation tools such as FDTD, RCWA, Ray-tracing, Macleod, etc. Recently, we are interested in designing nanostructure for application such as meta-lens, meta-surface, and NIR blocking films using optical simulation. Also, we are focusing on fabrication of nanostructures with various methods such as plasma treatment, nano-imprint, nano-sphere coating, anodization, VLS growth, hydrothermal growth, and pulse plating. The fabricated nanostructures are applied in various fields such as light-emitting devices, solar cells, and catalysts.
Nowadays, we are interested in research on the catalyst field, which has recently been in the spotlight. Our research goal is to explore and design the catalysts for highly efficient CO2 reduction, oxygen evolution reaction, and oxygen reduction reaction. We are focused on increasing the active sites using nanostructures, increasing the efficiency using bi-metal, and fabricating catalysts spontaneously. We also focused on demonstration of monolithic catalyst combined with solar cell, which can operate without external applied power.
Other research goal at NDDL is the improving the optical/electrical efficiency of GaN-based LEDs, which are attracting attention as next-generation light-emitting devices. We are focusing on improving light extraction efficiency through nanostructures using various methods such as nano imprint, dry etching, and wet etching. Also, we are interested in improving the characteristics of contact electrodes via surface & heat treatment. We are studying optical/electrical properties of fabricated LEDs and analysis using various simulation tools such as FDTD and ray-tracing.
Our group is focused on physics and technology at the OLED for next-generation flexible OLED platforms. The group leads in the design and fabrication of flexible substrates such as plastic, extremely flat metal. Also, our research is focused on design and fabrication of transparent electrodes such as thin metal and DMD structure. The group’s focus includes the enhancement of light extraction efficiency of OLED with various nanostructures such as MgO nano-facet embedded in active layer and air-gap embedded in flexible substrate. The device structure is designed by numerous optical simulation tool such as RCWA, Macleod, SimOLED, FDTD, and Ray-tracing. Through our research, we are applying optimized OLED to various next-generation fields such as display, solid-state lighting, virtual reality, and augmented reality.
The other research goal is developing high efficiency solar cells by designing electrodes with nanostructures, controlling the surface characteristics using interfacial layer, and fabricating highly transparent electrodes. In particular, we are focusing on increasing light absorption by ITO branches and Mgo nano-facet, optimizing the DMD transparent electrode structure, and improving hole extraction through IrOx. Through various optical simulations, we analyze the reason for the increment of efficiency from experimental results.