Selective charge doping of chemical vapor deposition-grown graphene by interface modification

Abstract

The doping and scattering effect of substrate on the electronic properties of chemical vapor deposition (CVD)-grown graphene are revealed. Wet etching the underlying SiO2 of graphene and depositing self-assembled monolayers (SAMs) of organosilane between graphene and SiO2 are used to modify various substrates for CVD graphene transistors. Comparing with the bare SiO2 substrate, the carrier mobility of CVD graphene on modified substrate is enhanced by almost 5-fold; consistently the residual carrier concentration is reduced down to 1011 cm−2. Moreover, scalable and reliable p- and n-type graphene and graphene p-n junction are achieved on various silane SAMs with different functional groups.

Relationship between the dipole moment of self-assembled monolayers incorporated in graphene transistors and device electrical stabilities

“…3d), corresponding well with the previous reports. 17,19,20,[27][28][29] The lone pair electrons in the amine groups have electron donating characteristic, thereby leading to the up-shi of Fermi level (n-doping). In addition, the large dipole moment of APS SAMs triggers a considerable hysteresis in the dual sweeps.…”

Experimental and computational investigation of graphene/SAMs/n-Si Schottky diodes

“…tionally, SAMs are promising materials in organic electronics due to the their flexibility in the chemical structure (choosing convenient donor and acceptor groups) [19], ability in changing the physical properties (such as absorbance spectrum, extinction coefficient and energy levels) [20], easy to synthesized and purified [19,20]. In recent studies, SAMs in graphene field effect transistors have been used as a seed layer in graphene-dielectric interface to improve device performance [21,22,23,[24][25][26][27][28][29][30]35]. Common aim of these studies are to passivate dielectric surface with SAMs resulting in reducing charge traps at the graphene-dielectric interface, limiting unintentional doping and increasing field effect mobility.…”

Low-temperature quantum transport in CVD-grown single crystal graphene

“…The upper x-axis of Fig. 1 shows the back-gate voltage converted to carrier concentration n ≈ CG|VBG -VDirac|/e [35], where CG is the gate capacitance per area (11.5 nF/cm 2 , for 300 nm oxide) and e is the elementary charge. The mobility μ of our devices was obtained using the formula μ = 1/neρ, with ρ the resistivity at B = 0 T. The four point mobility away from the Dirac point is 8200 cm 2 V -1 s -1 for Device-1, while for Device-2 we obtained 11000 cm 2 V -1 s -1 .…”