Conductive Nanorods in DLC Films Caused by Carbon Transformation

Abstract

The influence of diamond-like carbon (DLC) films deposited under various conditions on the electron field emission (EFE) of silicon (Si) tips has been investigated. During the nitrogendoped DLC film deposition, the nitrogen content in a gas mixture is varied from 0% to 45%. In this context, the effective work function is optimized, by reaching the values less than 1 eV. A sharp increase in the emission current at high electric fields and a decrease of the threshold voltage after the pre-breakdown conditioning of a DLC film on Si tips have been measured. At high current densities and the resulting local heating, the diamond-like 3 phase transforms into a conducting graphite-like 2 phase. As a result, an electrical conducting nanostructured channel is formed in the DLC film. The diameter of the conducting nanochannel is estimated from the reduced threshold voltage after the pre-breakdown conditioning to be in the interval 5-25 nm. The presence of this nanochannel in the insulating matrix leads to a local enhancement of the electric field and a reduced threshold voltage for EFE. The obtained results can be used for the development of highly efficient field emission cathodes. To explain the experimental EFE results based on a transformation of DLC films and the generation of conduction nanochannels, the changes of the electron affinity (0) for various carbon structures and impurity point defects have been calculated. The influence of the rehybridization of bonds in various carbon crystal structures on 0 is shown. The formation of conducting channel arrays in DLC films will allow us to significantly enhance EFE even on flat surfaces without tips. K e y w o r d s: diamond-like carbon film, electron field emission, conductive nanorods, carbon nanotube.

Kinetic modeling of the electronic response of a dielectric plasma-facing solid

“…The masses we take are the ones for a hydrogen plasma and a Si or a SiO 2 surface. In the energy range where we need the (effective) masses of the wall's charge carriers they are a bit uncertain [40,41,42]. We used therefore the mass of the conduction band electrons as a parameter to be varied within physically reasonable bounds.…”

Effect of the thickness on electrical resistance of thin diamond-like carbon coatings on silicon substrate

“…3, a, the transverse VAC structures W//DLC//Si//W, consisting of samples and tungsten contacts (W), measured at offset voltages in the range from −5 to 5 V, are nonlinear and asymmetric. In addition, during the measurements, a certain offset relative to zero on the stress scale was observed, not exceeding 0.1 V, which was for DLC the output work is much smaller and has an order of magnitude of 1 eV [18]. The height of the potential barrier ϕ b determines the density of charge carriers injected from the metal into the dielectric.…”

Влияние Толщины На Удельное Электросопротивление Тонких Покрытий Из Алмазоподобного Углерода На Кремнии

“…Кроме того, в ходе измерений наблюдалось некоторое смещение относительно нуля по шкале напряжений, не превышавшее 0.1 V, которое для корректности анализа было отцентрировано. Нелинейность и асимметричность ВАХ могут быть обусловлены формированием барьеров Шоттки на границах игла-кремний и игла-DLC: работа выхода электронов для вольфрама составляет 4.5 eV [17], для кремния, легированного бором ≈ 4.3 eV [17], для DLC работа выхода значительно меньше и имеет порядок величины 1 eV [18].…”