Temperature-induced strain and doping in monolayer and bilayer isotopically labeled graphene

An overview of the interaction between monolayer graphene and SiO2 dielectric substrate is reported focusing on the effect this latter has on doping and strain induced by thermal treatments in controlled atmosphere. The disentanglement of strain and doping is highlighted and the comparison with another dielectric substrate of Al2O3 evidences the critical role that the substrate has in the electronic properties of graphene. The reported results pave the way for microelectronic devices based on graphene on dielectrics and for Fermi level tuning in composites of graphene and nanoparticles.

Section: Resultsmentioning

confidence: 57%

“…The strain limit line (slope 2.45) is marked in solid black and the doping limit line (slope 0.7) in dashed gray, as reported in ref. for 532 nm laser excitation. Reproduced with permission .…”

Section: Resultsmentioning

confidence: 99%

Graphene‐SiO₂ Interaction from Composites to Doping

Armano

Buscarino

Cannas

et al. 2019

“…The large number of spectra collected in the Raman imaging allows to build a correlation map of the 2D peak position, POS(2D), as a function of the G peak position, POS(G), to obtain information on the presence of strain or doping and separate their contribution . In Figure the maps of CDs aqueous dispersion deposited on Gr1 (Figure a) and CDs ethanol dispersion deposited on Gr2 (Figure b) for excitation energy of 2.33 eV are reported. The point placed at 1582 cm −1 and 2670 cm −1 (black star in the correlation map) corresponds to the Raman shift of ideal graphene, with no stress and doping; from this point two reference lines are plotted, with slope 2.45 and 0.7, indicating pure strain and pure doping, respectively .…”

Section: Resultsmentioning

confidence: 99%

Carbon Dots Dispersed on Graphene/SiO₂/Si: A Morphological Study

Faggio

Gnisci

Messina

et al. 2019

Low‐dimensional carbon materials occupy a relevant role in the field of nanotechnology. Herein, the authors report a study conducted by atomic force microscopy and Raman spectroscopy on the deposition of carbon dots onto graphene surfaces. The study aims at understanding if and how the morphology and the microstructure of chemical vapor deposited graphene on Si/SiO2 may change due to the interaction with the carbon dots. Potential alteration in the graphene's electrical properties might be detrimental for optoelectronic applications. The deposition of carbon dots dispersed in water and ethanol solvents are explored to investigate the effect of solvents with different fluidic properties. The obtained results indicate that the carbon dots do not alter the quality of graphene.

“…The points are located between two axes that describe the pure strain with a slope of 2.45 (solid black line in Figure ) and the pure doping with a slope of 0.7 (solid gray line in Figure ). The origin of this coordinate system (1582 cm −1 , 2670 cm −1 ) corresponds to undoped and unstrained graphene for excitation energy equal to 2.33 eV . The point distribution in the map is due to in‐homogeneity of the sample but it was possible to extimate doping and strain evaluating the center of point cluster …”

Section: Resultsmentioning

confidence: 99%

“…The origin of this coordinate system (1582 cm −1 , 2670 cm −1 ) corresponds to undoped and unstrained graphene for excitation energy equal to 2.33 eV . The point distribution in the map is due to in‐homogeneity of the sample but it was possible to extimate doping and strain evaluating the center of point cluster …”

Section: Resultsmentioning

confidence: 99%

The Role of Graphene‐Based Derivative as Interfacial Layer in Graphene/n‐Si Schottky Barrier Solar Cells

Gnisci¹,

Faggio²,

Lancellotti

et al. 2018

Schottky‐barrier solar cells (SBSCs) represent low‐cost candidates for photovoltaics applications. The engineering of the interface between absorber and front electrode is crucial for reducing the dark current, blocking the majority carriers injected into the electrode, and reducing surface recombination. The presence of tailored interfacial layers between the metal electrode and the semiconductor absorber can improve the cell performance. In this work, the interface of a graphene/n‐type Si SBSC by introducing a graphene‐based derivative (GBD) layer meant to reduce the Schottky‐barrier height (SBH) and ease the charge collection are engineered. The chemical vapor deposition (CVD) parameters are tuned to obtain the two graphene films with different structure and electrical properties: few‐layer graphene (FLG) working as transparent conductive electrode and GBD layer with electron‐blocking and hole‐transporting properties. Test SBSCs are fabricated to evaluate the effect of the introduction of GBD as interlayer into the FLG/n‐Si junction. The GBD layer reduces the recombination at the interface between graphene and n‐Si, and improves the external quantum efficiency (EQE) with optical bias from 50 to 60%. The FLG/GBD/n‐Si cell attains a power conversion efficiency (PCE) of ≈5%, which increase to 6.7% after a doping treatment by nitric acid vapor.