Su Woong Lee

Metal bonded carrier for high electron emission carbon nanotube emitters

We introduced the metal bonded silicon substrate as Al cathode for reduced contact resistance. The Si-Al was bonded in vacuum system with temperature of 570 °C and 15 min annealing time. After eutectic bonding, the resistance is reduced to a couple of ohms. The resistance was reduce to one hundreds of initial value. The electron emission current increased after Si-Al bonding. And the stability of emission current of the eutectic bonded CNT emitter shows improved.

Fabrication of highly stable carbon nanotube electron beams(C-beam)

We optimized the triode structure for carbon nanotube electron beam(C-beam) application with carbon nanotube emitters grown with resist-assisted pattering process. The CNT emitters grown through the RAP process have a structure in which a number of CNTs are congregated, and the graphitization post-treatment process proceeded in order to enhance their adhesive strength and stability. The gate mesh was self-aligned with the carbon nanotube island for lower leakage current, resulting higher electron emission current and transmission ratio. With the optimized triode structure, the emission current show high performance with less than 1 cm2 area and C-beams operated more than 500 hours with constant current mode and DC driving.

Enhanced field emssion properties of paste CNT emitters with nickel buffer layer

Stable field emitters were developed using carbon nanotubes (CNTs) composite pastes with nickel (Ni) buffer layer. The paste CNT emitters showed lower threshold for field emission but which have short lifetime and unstable emission current in high emission current. In this paper, we developed the simple process of inserting Ni buffer layer between the CNT emitters and substrate. The paste CNT emitters with Ni buffer layer showed enhanced field emission properties than bare one. The lifetime of paste CNT emitters with Ni buffer layer were 9 hours 40 min. Its 22 times longer than without buffer layered one.

High performance carbon nanotube emitters beam (C-beam) for display device application

We introduced a carbon nanotube electron beam (C-beam) exposure technique for thin films for display devices. As an electron source, the CNT emitters were placed on cathode electrode. Electrons through gate mesh, with higher accelerated energy, impact thin film on the anode plate. For display device application, amorphous silicon (a-Si:H) thin films were deposited on glass substrate and then C-beams exposed. After moderated C-beam exposure, the silicon film changes to phase of crystalline one. The structural modification was confirmed with Raman spectrum and the enhanced electrical performances were measured with I-V systems. The silicon crystalline properties were strongly depending on the C-Beam exposure conditions.

Cathodoluminescence properties of ZnO thin films with the carbon nanotube emitters beam (C-beam) exposure

In this study, we optimized vertically aligned carbon nanotube electron beam (C-beam) with triode structure for cathodoluminescence of Zinc Oxide (ZnO) thin films, which solution process fabricated. Efficient cathodoluminescences were observed with C-beam exposed ZnO thin films. The origin of the luminescence were confirmed by SEM measurement. The luminescence appeared to the structural modification of thin ZnO films after C-beam exposure, resulting nano-crystalline film formation.

Enhanced field emission with self-alingned carbon nanotube emitters grown by RAP process

We optimized the triode structure for field emission with carbon nanotube emitters grown with resist-assisted pattering process. Carbon nanotube emitters were grown on silicon substrate and patterned with grid mesh for structural optimization. The gate mesh was self-aligned with the carbon nanotube for lower leakage current, resulting higher electron emission current and transmission ratio. With the optimized triode structure, we fabricated field emission lamp and obtain luminance of 23,000 cd/m2.

Cathodoluminescence properties of silicon thin films crystallized by electron beam exposure

In this study, we investigated cathodoluminescence properties from silicon thin film after electron beam exposure on amorphous silicon film. The emission spectrum shows broad distribution in the visible region. Raman spectroscopy and SEM measurement shows that the area exposed by E-beam is crystallized. However the intensities of CL spectra of a-Si weakly appeared at 500 ~ 800 nm. The origin of CL spectrum from the silicon film exposed by E-beam will be discussed.