Multiscale Analysis for Field-Effect Penetration through Two-Dimensional Materials
Data(s) |
2016
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Resumo |
Gate-tunable two-dimensional (2D) materials-based quantum capacitors (QCs) and van der Waals heterostructures involve tuning transport or optoelectronic characteristics by the field effect. Recent studies have attributed the observed gate-tunable characteristics to the change of the Fermi level in the first 2D layer adjacent to the dielectrics, whereas the penetration of the field effect through the one-molecule-thick material is often ignored or oversimplified. Here, we present a multiscale theoretical approach that combines first-principles electronic structure calculations and the Poisson–Boltzmann equation methods to model penetration of the field effect through graphene in a metal–oxide–graphene–semiconductor (MOGS) QC, including quantifying the degree of “transparency” for graphene two-dimensional electron gas (2DEG) to an electric displacement field. We find that the space charge density in the semiconductor layer can be modulated by gating in a nonlinear manner, forming an accumulation or inversion layer at the semiconductor/graphene interface. The degree of transparency is determined by the combined effect of graphene quantum capacitance and the semiconductor capacitance, which allows us to predict the ranking for a variety of monolayer 2D materials according to their transparency to an electric displacement field as follows: graphene > silicene > germanene > WS2 > WTe2 > WSe2 > MoS2 > phosphorene > MoSe2 > MoTe2, when the majority carrier is electron. Our findings reveal a general picture of operation modes and design rules for the 2D-materials-based QCs. |
Identificador | |
Idioma(s) |
eng |
Direitos |
info:eu-repo/semantics/closedAccess |
Fonte |
Tian , T , Rice , P , Santos , E J G & Shih , C-J 2016 , ' Multiscale Analysis for Field-Effect Penetration through Two-Dimensional Materials ' Nano Letters , vol 16 , no. 8 , pp. 5044-5052 . DOI: 10.1021/acs.nanolett.6b01876 |
Palavras-Chave | #ab initio calculations #field effect #graphene #quantum capacitance #transition metal dichalcogenides #two-dimensional materials |
Tipo |
article |