Role of growth temperature on nanostructure and field emission properties of PLD thin carbon films |
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Authors: | C Scilletta S Orlando M Servidori E Cappelli G Conte P Ascarelli |
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Institution: | (1) CNR-ISC, Montelibretti, via Salaria Km 29.3, P.O.B. 10, 00016 Monterotondo, Rome, Italy;(2) CNR-IMIP, Potenza, 85050 Tito Scalo, Potenza, Italy;(3) CNR-IMM, Bologna, Via P. Gobetti 101, 40129 Bologna, Italy;(4) Department of Electronic Engineering and CNISM, University of Rome “Roma Tre”, Via della Vasca Navale 84, 00146 Rome, Italy |
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Abstract: | Thin carbon films have been deposited in vacuum (∼10−4 Pa) on Si substrates by pulsed laser ablation of a graphite target using a Nd:YAG laser operating in the near infrared region
(λ=1064 nm). The samples have been deposited at different substrate temperatures (T
sub) ranging from room temperature (RT) to 800°C. X-ray diffraction analysis established the progressive formation of nanosized
graphene structures as T
sub increased. In fact, film structure evolves from almost amorphous to nanostructured phase characterized by graphene layers
oriented perpendicularly to the film plane. The film density, evaluated by X-ray reflectivity measurements, is strongly affected
by T
sub. At RT the film density is similar to the graphite one, while it decreases at higher T
sub. The electrical properties of the samples have been characterized by field emission measurements. The parameters describing
the emitter properties (threshold field E
th and field enhancement factor β) have been evaluated using variable anode-to-cathode distance method. Samples deposited at low T
sub have shown the best emission properties, presenting lower E
th and larger β values than those deposited at higher T
sub. This is mainly attributed to the sensible density variation, which is in competition with the slighter augment of mean nanoparticle
size. |
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Keywords: | PACS" target="_blank">PACS 81 15 Fg 61 48 De 79 70 +q |
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