In Situ Raman Spectroscopy of Solution-Gated Graphene on Copper

Abstract

We present a solution-gated in situ Raman spectroscopy approach, which enables the electrical characterization of graphene on a copper substrate without the need of a transfer process. The application of a voltage across the solution resulted in a shift of the Raman G-band without a significant shift of the 2D band. This observation allowed for the separation of the effects of strain and doping. Based on the G and 2D band shifts we show that we can manipulate the n-type carrier concentration of graphene directly on the copper substrate in a range from about 8 × 10 12 cm −2 to about 1.5 × 10 13 cm −2 .

Suspended graphene on germanium: selective local etching via laser-induced photocorrosion of germanium

“…The thinner dashed parallel lines are offset by a change in strain of 0.1 %. As values for undoped, freestanding graphene we assumed ω 0 G = 1580 cm −1 and ω 0 2D = 2671 cm −1 [41][42][43][44], where the 2D value was corrected for the employed laser wavelength (532 nm) [45]. The black circles correspond to measurements on the membrane and the blue squares were recorded in the unexposed, germanium supported region.…”