Experimental study of quantum size effects in very thin metal films

Stark, D.; Zwicknagl, P.

doi:10.1007/bf00895932

Cited by 14 publications

(2 citation statements)

References 18 publications

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“…Their number and sharpness were found to increase with the length of the tubes. Notice that short periodic variations were also observed in the thickness-dependent field emission current from ultrathin metal films (UMF) [9]. The calculated electron energy distribution curve characteristic of UMF was found to have "steps" which correspond with the quantized "normal" energies [10].…”

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Energy distributions of field emitted electrons from carbon nanosheets: Manifestation of the quantum size effect

Katkov

Osipov

2009

Jetp Lett.

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We emphasize the importance of experiments with voltage dependent field emission energy distribution analysis in carbon nanosheets. Our analysis shows the crucial influence of the band structure on the energy distribution of field emitted electrons in few-layer graphene. In addition to the main peak we found characteristic sub-peaks in the energy distribution. Their positions strongly depend on the number of layers and the inter-layer interaction. The discovery of these peaks in field emission experiments from carbon nanosheets would be a clear manifestation of the quantum size effect in these new materials. Recently, freestanding carbon nanosheets (CNSs) have been synthesized on a variety of substrates by radio frequency plasma enhanced chemical vapor deposition [1,2]. The sheets are consisting of several graphene layers and stand roughly vertical to the substrate. It has been found that CNSs have good field emission characteristics with promising applications in vacuum microelectronic devices [3,4,5,6]. High emission total current at low threshold field enables using CNSs as an effective cold cathode material.Until now only the current-voltage characterization was used in studies of CNSs. At the same time, voltage dependent field emission energy distribution (V-FEED) analysis is known as a powerful experimental method to interrogate the field emission. As compared to classical I-V characterization, V-FEED analysis can provide more information related to both inherent properties of the emitter and to the basic tunneling process [7]. In particular, in single-walled carbon nanotubes (CNTs) the FEED has shown characteristic peaks originated from the stationary waves in the cylindrical part of the nanotube [8]. Their number and sharpness were found to increase with the length of the tubes. Notice that short periodic variations were also observed in the thickness-dependent field emission current from ultrathin metal films (UMF) [9]. The calculated electron energy distribution curve characteristic of UMF was found to have "steps" which correspond with the quantized "normal" energies [10]. The resonant-tunneling peaks with specific microscopic tunneling mechanisms were also observed in field emission from nanostructured semiconductor cathodes [11]. A different example of the quantum size effect in CNTs, which originates from the intrinsic properties of the energy band structure, was revealed in field emission [12]. It is reasonable to expect manifestation of quantum size effects in subnanometer CNSs.

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