Despite intensive investigations in the UV (ultraviolet) and visible range, the research on the optical properties of graphene in the extended near and mid infrared range by means of Spectroscopic Ellipsometry (SE) remains limited yet. Herein, the optical properties of a Chemical Vapor Deposition (CVD)-grown monolayer graphene, transferred from a copper substrate onto SiO2/Si, were studied in the broad energy range (0.38-6.2 eV) using Variable Angle Spectroscopic Ellipsometry (VASE). The morphological and the structural properties of the samples were investigated by Micro-Raman Spectroscopy, Wavelength Dispersive X-ray (WDX) analysis, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The Lorentz oscillator model proposed for the optical response of graphene fits very well the experimental data. An unintentional doping, revealed by Micro-Raman Spectroscopy and WDX, is reported.
Nonostante le intense indagini nella regione UV-VIS, la ricerca sulle proprietà ottiche del grafene nella gamma estesa del vicino e medio infrarosso mediante Ellipsometria Spettroscopica (SE) rimane ancora limitata. Nel presente documento, le proprietà ottiche di un monostrato di grafene ottenuto per deposizione chimica da vapore (CVD), trasferito su SiO2 / Si da un substrato di rame , sono state studiate nell'ampio intervallo di energia (0,38-6,2 eV) utilizzando l'ellissometria spettroscopica ad angolo variabile (VASE). Le proprietà morfologiche e strutturali dei campioni sono state studiate mediante spettroscopia Micro-Raman, analisi a raggi X a dispersione di lunghezza d'onda (WDX), microscopia elettronica a scansione (SEM) e microscopia a forza atomica (AFM). Il modello ad oscillatori di Lorentz proposto per la risposta ottica del grafene si adatta molto bene ai dati sperimentali. Viene segnalato un doping non intenzionale, rivelato dalla spettroscopia Micro-Raman e da WDX.
Variable Angle Spectroscopic Ellipsometry investigation of CVD-grown monolayer graphene
Castriota Marco;De Santo Maria Penelope;Desiderio Giovanni;
2019
Abstract
Despite intensive investigations in the UV (ultraviolet) and visible range, the research on the optical properties of graphene in the extended near and mid infrared range by means of Spectroscopic Ellipsometry (SE) remains limited yet. Herein, the optical properties of a Chemical Vapor Deposition (CVD)-grown monolayer graphene, transferred from a copper substrate onto SiO2/Si, were studied in the broad energy range (0.38-6.2 eV) using Variable Angle Spectroscopic Ellipsometry (VASE). The morphological and the structural properties of the samples were investigated by Micro-Raman Spectroscopy, Wavelength Dispersive X-ray (WDX) analysis, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The Lorentz oscillator model proposed for the optical response of graphene fits very well the experimental data. An unintentional doping, revealed by Micro-Raman Spectroscopy and WDX, is reported.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.