Geun Ju Kim

Silicon based micro-scale metal grid for field emission device

For application to electron field emission devices, a metal grid based on a silicon frame is introduced. Silicon frame is used to improve the thermal resistivity and electrical stability by electron beam. Silicon based micro-scale metal grid fabricated using MEMS technology.

Silicon-based metallic micro grid for electron field emission

A micro-scale metal grid based on a silicon frame for application to electron field emission devices is introduced and experimentally demonstrated. A silicon lattice containing aperture holes with an area of 80 × 80 µm2 and a thickness of 10 µm is precisely manufactured by dry etching the silicon on one side of a double-polished silicon wafer and by wet etching the opposite side. Because a silicon lattice is more rigid than a pure metal lattice, a thin layer of Au/Ti deposited on the silicon lattice for voltage application can be more resistant to the geometric stress caused by the applied electric field. The micro-fabrication process, the images of the fabricated grid with 88% geometric transparency and the surface profile measurement after thermal feasibility testing up to 700 °C are presented.

Electron energy enhancement using plasma density increment in laser wakefield acceleration

The effect of the plasma density structure on the electron energy in laser wakefield acceleration is studied. Using a simple rotatable supersonic nozzle, the plasma density structure is controlled. Two dimension particle in cell simulation indicates that due to the decrease of the size of the acceleration field cavity with increasing density structure, the electron energy is enhanced. Using 20 TW laser system, the laser wakefield acceleration with density increment structure was conducted. The results show the enhancement of the electron energy with the density increment structure.