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Tunable and sizable band gap in silicene by surface adsorption
Ruge Quhe1, Ruixiang Fei, Qihang Liu
1State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, P R China.
Scientific Reports
|November 16, 2012
Summary
Alkali atom adsorption opens a band gap in silicene, crucial for high-performance field effect transistors (FETs). This method allows tunable band gaps and high on/off ratios, paving the way for silicene-based electronics.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Silicene, a silicon analogue of graphene, requires a sizable band gap for field-effect transistor (FET) applications.
- Maintaining high carrier mobility alongside band gap opening is a key challenge for silicene.
Purpose of the Study:
- To investigate the effect of alkali atom adsorption on opening a band gap in silicene.
- To explore the tunability of the band gap size and its impact on carrier mobility.
- To assess the performance of silicene in a bottom-gated FET configuration.
Main Methods:
- Density functional theory (DFT) calculations were employed to model silicene structures.
- Ab initio quantum transport simulations were performed on sodium-covered silicene FETs.
Main Results:
- Single-side adsorption of alkali atoms effectively opens a band gap in silicene by breaking sublattice/bond symmetry.
- The band gap size is controllable via alkali atom coverage, reaching up to 0.50 eV.
- Quantum transport simulations showed a transport gap consistent with the DFT-predicted band gap, yielding an on/off current ratio of 10^8.
Conclusions:
- Alkali atom adsorption provides a viable route to engineer the electronic properties of silicene.
- Silicene functionalized with alkali atoms demonstrates potential for high-performance FET applications.
- This research paves the way for utilizing silicene as a channel material in advanced electronic devices.
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