Dae-Jun Kim

Novel tapered macrogate structure for carbon nanotube based field emission display

The tapered macrogate (TMG) structure is proposed to overcome the difficulties in carbon nanotube (CNT) based field emission display (FED) with high-voltage phosphors used in cathode ray tube screens. In order to achieve an ideal triode operation for field emission devices, the TMG was designed to have a very thick gate insulator with the inclined gate holes compared with the CNT emitters. The inclined gate holes with a narrower outlet than the bottom of the hole were shown to protect the CNT emitters from the anode field perfectly, enabling the authors to apply a high anode voltage over 10 kV needed for high-voltage FED. Also, the TMG structure had additional useful functions such as an electron-beam self-focusing and high durability against electrical damage. The authors successfully fabricated and demonstrated a 5 in. active-matrix CNT-FED panel with the TMG, showing color moving images with a low addressing voltage of about 15 V using amorphous silicon thin-film transistor as a switching device.

Fabrication of subwavelength-size aperture for a near-field optical probe using various microfabrication procedures

We successfully fabricated subwavelength-size silicon oxide apertures on a cantilever array as a near-field optical probe. Various semiconductor processes were utilized for subwavelength-size aperture fabrication. The anisotropic etching of the Si substrate by alkaline solutions followed by anisotropic crystal orientation dependent oxidation, anisotropic plasma etching, and isotropic oxide etching was carried out. 2, 3, and 4 μm size dot arrays were initially photolithographically patterned on a Si(100) wafer. After fabrication of a V-groove shape by anisotropic etching, oxide growth at 1000 °C was performed to have an oxide etch mask. The oxide layer on the Si(111) plane has been utilized as an etch mask for plasma dry etching and water-diluted HF wet etching for subwavelength-size aperture fabrication. A Au thin layer was deposited on the fabricated oxide aperture on the cantilever array. After this procedure, the initial opening, 300 nm of the oxide aperture was reduced down to ∼95 nm.

63.3: Active-Matrix Cathodes with Tapered Macro-Gate for High-Performance Field Emission Display

A color field emission display was developed with active-matrix cathodes and tapered macro-gate (TMG). The cascade-connected a-Si TFTs exhibited well controlled field emissions from carbon nanotube (CNT) emitters. The TMG protected the CNT emitters from the anode field perfectly, enabling us to apply a high anode voltage over 10 kV.

Development of a compact X-ray tube with CNT field emitters

We have investigated the potential of screen printed CNT field emitters for improving the efficiency and reliability of compact X-ray tubes, and then we have fabricated and tested about our compact X-ray tube with ceramic body using ceramic brazing vacuum sealing technique.

P-124: Highly Reliable CNT Emitters with Enhanced Adhesion to Cathode Electrode

Highly reliable carbon nanotube (CNT) emitters were obtained by optimizing the paste composition along with a nano-scale metal filler. The nano-scale filler strongly enhanced adhesion between CNT emitter and cathode electrode. The developed CNT emitters showed great improvements in field emission properties including the effective density, uniformity, and reliability.

A novel gate structure for a miniature X-ray tube based on CNT emitters

We suggest a novel gate structure, Focusing-Functional Gate (FFG), having a focusing effect on the electron beams from the carbon nanotube (CNT) emitters for the miniature X-ray tubes. The FFG induced field emission from the CNT emitters and focused electron beams into the anode target without an additional focusing electrode, resulting in a small focal spot with little charging at the insulating body of the X-ray tube. We have successfully obtained a stable emission current and images from the miniature X-ray tube with the FFG.

The design and fabrication of CNT field emitters for a vacuum-sealed X-ray tube

We have designed and fabricated a highperformance carbon nanotube (CNT) field emitter for a vacuum-sealed X-ray tube by a brazing process. The developed high-temperature endurable CNT emitters were vacuum-sealed in the diode and triode configurations, showing little degradation upon the brazing process and a good cold cathode of X-ray tube.