Theoretical study of scattering in graphene ribbons in the presence of structural and atomistic edge roughness

We investigate the diffusive electron-transport properties of charge-doped graphene ribbons and nanoribbons with imperfect edges. We consider different regimes of edge scattering, ranging from wide graphene ribbons with (partially) diffusive edge scattering to ribbons with large width variations and nanoribbons with atomistic edge roughness. For the latter, we introduce an approach based on pseudopotentials, allowing for an atomistic treatment of the band structure and the scattering potential, on the self-consistent solution of the Boltzmann transport equation within the relaxation-time approximation and taking into account the edge-roughness properties and statistics. The resulting resistivity depends strongly on the ribbon orientation, with zigzag (armchair) ribbons showing the smallest (largest) resistivity and intermediate ribbon orientations exhibiting intermediate resistivity values. The results also show clear resistivity peaks, corresponding to peaks in the density of states due to the confinement-induced subband quantization, except for armchair-edge ribbons that show a very strong width dependence because of their claromatic behavior. Furthermore, we identify a strong interplay between the relative position of the two valleys of graphene along the transport direction, the correlation profile of the atomistic edge roughness, and the chiral valley modes, leading to a peculiar strongly suppressed resistivity regime, most pronounced for the zigzag orientation.Comment: 13 pages, 7 figure

Progetto di concorso per la nuova Biblioteca civica di Bressanone

Elaborati di progetto per il concorso per la nuova Biblioteca civica di Bressanone

Understanding Porous Crystal Growth By Scanning Electron Microscopy

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Modeling of Edge Scattering in Graphene Interconnects

© 1980-2012 IEEE. Graphene interconnects are being considered as a promising candidate for beyond CMOS applications, thanks to the intrinsic higher carrier mobility, lower aspect ratio and better reliability with respect to conventional Cu damascene interconnects. However, similarly to Cu, line edge roughness can seriously affect graphene resistance, something which must be taken into account when evaluating the related performance benefits. In this letter, we present a model for assessing the impact of edge scattering on the resistance of graphene interconnects. Our model allows the evaluation of the total mean free path in graphene lines as a function of graphene width, diffusive scattering probability and edge roughness standard deviation and autocorrelation length. We compare our model with other models from literature by benchmarking them using the same set of experimental data. We show that, as opposed to the considered models from literature, our model is capable to describe the mobility drop with scaling caused by significantly rough edges.status: publishe

Evaluation of multilayer graphene for advanced interconnects

In this work we are electrically characterizing multilayer graphene ribbons as potential Cu replacement towards future interconnect applications. We are comparing their performance with single-layer ribbons and we are reporting on sheet resistance, mobility and mean free path. We are additionally characterizing the contact properties for Pd contacts in top and edge configuration. Our results show high current carrying capacity for the multilayer ribbons and lower sheet resistance. Edge contacts tomultilayer ribbons seema promising approach for the decrease of the contact resistivity. Values of sheet resistance Rs ~280 Ω and contact resistivity Rc*W ~325 Ω·μm are measured for multilayer samples and edge contacts. Although the calculated ribbon mean free path is high for single-layer graphene (MFPSLG ~60 nm), it is comparablewith the MFP of Cu for themultilayer samples (MFPFLG ~30 nm). Intercalation is a potential approach for improvement of the multilayer wire properties.publisher: Elsevier articletitle: Evaluation of multilayer graphene for advanced interconnects journaltitle: Microelectronic Engineering articlelink: http://dx.doi.org/10.1016/j.mee.2016.09.011 content_type: article copyright: © 2016 Elsevier B.V. All rights reserved.status: publishe

Doping of graphene for the application in nano-interconnect

Graphene is considered as potential candidate for future nano-interconnects. In this respect we study the Brønsted acid doping effect of single layer graphene (SLG) and fewlayer graphene (FLG) synthesized by chemical vapor deposition (CVD). A sheet resistance reduction of 50% is achieved by HNO3 doping of SLG, and the resulting resistivity of 9.1 μ Ω·cmis comparable to alternative metals to copper (e.g. Ru). On the other hand, synthetic FLG shows higher sheet resistance due to higher defect density. Mobility degradation at increased carrier concentration is a main limiting factor for sheet resistance reduction of CVD graphenepublisher: Elsevier articletitle: Doping of graphene for the application in nano-interconnect journaltitle: Microelectronic Engineering articlelink: http://dx.doi.org/10.1016/j.mee.2016.10.013 content_type: article copyright: © 2016 Elsevier B.V. All rights reserved.status: publishe