KrF laser surface treatment of carbon nanotube cathodes with and without reactive ion etching

Abstract

Electron emission characteristics of carbon nanotube cathodes with and without reactive ion etching (RIE) followed by KrF laser irradiation were investigated. The emission characteristics of samples without RIE process, such as emission current density, turn-on field, and emission pattern, strongly depend on the laser power density, which is caused by a photon process at low laser power densities of 2–4MW∕cm2 and a thermal ablation at high power densities of 10–14MW∕cm2. The emission characteristics of samples with RIE, however, show little change when the laser power density is varied. Surface morphologies of CNT cathodes with RIE process show little change by laser treatment compared to the case of CNT cathodes without RIE process.

Effects of Laser Irradiation on the Thermal Conductivity and Viscosity of Aqueous Multiwalled Carbon Nanotube Suspensions

“…2f. Interactions between a UV laser beam and CNTs are related with the photothermal process as well as the photochemical process [27,28,31]. When a solid immersed in a liquid is irradiated by a short pulsed laser, in addition to the photochemical effect, the photothermal effect causes optical cavitation in the liquid [46,47].…”

“…In a similar manner, energetic ion beam irradiation changed the structure of MWCNTs due to the continued collisions of ions with carbon atoms, and the separate MWCNTs evolved into amorphous carbon nanowire networks [20][21][22]. Laser irradiation was used to purify CNTs by removing carbonaceous impurities, organic binders, or metallic catalysts or to create dangling carbon bonds which enhance emission properties in a CNT field emitter [23][24][25][26][27][28][29][30][31][32].…”

“…An ultraviolet (UV) laser with a relatively high photon energy is more efficient in purifying or damaging the CNTs than the visible and infrared lasers of the same power because a photochemical process (photodecomposition) and a photothermal process occur at the same time [26][27][28][29][30][31][32]. Photo-oxidation is also important in laser and CNT interactions.…”

Relationship between field-emission characteristics and defects measured by Raman scattering in carbon-nanotube cathodes treated by plasma and laser

“…The increased I D / I G ratios up to 3 MW/ cm 2 are mainly due to the bond breaking by incident photons. Since the photon energy ͑5.00 eV͒ of the excimer laser is much higher than that of the C-C bond ͑3.61 eV͒ in CNTs, 13 C-C bonds of CNT are broken to increase the dangling bonds of CNTs, resulting in the increased defects by the decreased number of hexagonal structure. However, a further increase in laser power density at and above 8 MW/ cm 2 starts to anneal CNTs, as well as defects of CNTs, by the thermal effect of the high-energy laser.…”

Effects of carbon nanotube diameters of the screen printed cathode on the field emission characteristics

“…In our previous studies, the field emission characteristics of screen printed CNT cathodes have been improved by several kinds of surface treatments such as focused ion beam, 3 laser irradiation, [4][5][6][7][8] Ar plasma treatment, 9,10 or tape peeling. These features are suitable for emitters of field emission displays ͑FEDs͒ or other field emission products.…”