Manipulation at a distance: Atomic-scale observation of ballistic electron transport in single layer graphene

2013 ◽  
Vol 102 (22) ◽  
pp. 223104 ◽  
Author(s):  
H. Yang ◽  
A. J. Mayne ◽  
C. Cejas ◽  
G. Dujardin ◽  
Y. Kuk
Keyword(s):  
Electron Transport ◽  
Single Layer ◽  
Atomic Scale ◽  
Single Layer Graphene ◽  
Layer Graphene ◽  
Ballistic Electron ◽  
Ballistic Electron Transport

scholarly journals Atomic Layer Deposition of Titanium Oxide on Single-Layer Graphene: An Atomic-Scale Study toward Understanding Nucleation and Growth

2017 ◽  
Vol 29 (5) ◽  
pp. 2232-2238 ◽  
Author(s):  
Yucheng Zhang ◽  
Carlos Guerra-Nuñez ◽  
Ivo Utke ◽  
Johann Michler ◽  
Piyush Agrawal ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Titanium Oxide ◽  
Single Layer ◽  
Atomic Layer ◽  
Nucleation And Growth ◽  
Atomic Scale ◽  
Single Layer Graphene ◽  
Layer Graphene ◽  
Layer Deposition

scholarly journals Macroscopic Assembled Graphene for Silicon Mid-Infrared Photodetectors

2020 ◽  
Author(s):  
Chao Gao ◽  
Li Peng ◽  
Sichao Du ◽  
Lixiang Liu ◽  
Srikrishna Bodepudi ◽  
...  
Keyword(s):  
Impact Ionization ◽  
Single Layer ◽  
Atomic Scale ◽  
Hot Electrons ◽  
Single Layer Graphene ◽  
Quantum Yields ◽  
Infrared Range ◽  
Mid Infrared ◽  
Hot Carrier ◽  
Layer Graphene

Abstract Graphene with linear energy dispersion and weak electron-phonon interaction is highly anticipated to harvest hot-electrons in a broad wavelength range from ultraviolet to terahertz. However, the limited absorption (~2.3%) and serious backscattering of hot-electrons associated with single-layer graphene result in inadequate quantum yields, impeding their practically broadband photodetection, especially in the mid-infrared range. Here, we report a macroscopic assembled graphene (MAG)/silicon heterojunction for ultrafast mid-infrared photodetection. The highly crystalline 2-inch scale MAG with tunable thickness from 10 to 60 nm is produced by scalable wet-assembly of commercial graphene oxide followed by thermal annealing. The MAG/Si Schottky diode exhibits broadband photodetection capability in 1-10 μm at room temperature with fast response (120-130 ns, 4 mm2 window) and high detectivity (1011 to 106 Jones), outperforming single-layer graphene/Si photodetectors by 2 to 8 orders in transient photocurrent. This optoelectronic performance is attributed to the superior advantages of MAG (~40% of light absorption, ~23 ps of carrier relaxation time, and high quasi-equilibrated hot-carrier-multiplication gain), atomic-scale contact interface of MAG and silicon, and impact-ionization avalanche gain (~100 times) from silicon. The MAG provides a long-range platform to understand the hot-carrier dynamics in stacked 2D materials, leading to next-generation broadband silicon-based image sensors.

Comparative study of electron transfer on various graphene-metallic contacts

2019 ◽  
Vol 33 (31) ◽  
pp. 1950384
Author(s):  
Di Lu ◽  
Yu-E Yang ◽  
Weichun Zhang ◽  
Caixia Wang ◽  
Jining Fang ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Single Layer ◽  
Annealing Treatment ◽  
Single Layer Graphene ◽  
Strain Effect ◽  
Graphene Surface ◽  
Layer Graphene ◽  
Metallic Contacts ◽  
Nonuniform Strain ◽  
Main Factor

We have investigated Raman spectra of the G and 2D lines of a single-layer graphene (SLG) with metallic contacts. The shift of the G and 2D lines is correlated to two different factors. Before performing annealing treatment or annealing under low temperature, the electron transfer on graphene surface is dominated by nonuniform strain effect. As the annealing treatment is enhanced, however, a suitable annealing treatment can eliminate the nonuniform strain effect where the relative work function (WF) between graphene and metal becomes a main factor to determine electronic transfer. Moreover, it is confirmed that the optimized annealing treatment can also decrease effectively the structural defect and induced disorder in graphene due to metallic contacts.

scholarly journals Millisecond lattice gasification for high-density CO2- and O2-sieving nanopores in single-layer graphene

2021 ◽  
Vol 7 (9) ◽  
pp. eabf0116
Author(s):  
Shiqi Huang ◽  
Shaoxian Li ◽  
Luis Francisco Villalobos ◽  
Mostapha Dakhchoune ◽  
Marina Micari ◽  
...  
Keyword(s):  
Single Layer ◽  
High Density ◽  
Single Layer Graphene ◽  
Pore Density ◽  
Vacancy Defects ◽  
Carbon Gasification ◽  
Layer Graphene ◽  
Gas Molecules ◽  
Good Agreement

Etching single-layer graphene to incorporate a high pore density with sub-angstrom precision in molecular differentiation is critical to realize the promising high-flux separation of similar-sized gas molecules, e.g., CO2 from N2. However, rapid etching kinetics needed to achieve the high pore density is challenging to control for such precision. Here, we report a millisecond carbon gasification chemistry incorporating high density (>1012 cm−2) of functional oxygen clusters that then evolve in CO2-sieving vacancy defects under controlled and predictable gasification conditions. A statistical distribution of nanopore lattice isomers is observed, in good agreement with the theoretical solution to the isomer cataloging problem. The gasification technique is scalable, and a centimeter-scale membrane is demonstrated. Last, molecular cutoff could be adjusted by 0.1 Å by in situ expansion of the vacancy defects in an O2 atmosphere. Large CO2 and O2 permeances (>10,000 and 1000 GPU, respectively) are demonstrated accompanying attractive CO2/N2 and O2/N2 selectivities.

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