Contact Resistance and Channel Conductance of Graphene Field-Effect Transistors under Low-Energy Electron Irradiation.
We studied the effects of low-energy electron beam irradiation up to 10 keV on graphene-based field effect transistors. We fabricated metallic bilayer electrodes to contact mono- and bi-layer graphene flakes on SiO₂, obtaining specific contact resistivity ρ c ≈ 19 k Ω · µ m 2 and carrier mobility as high as 4000 cm²·V-1·s-1. By using a highly doped p-Si/SiO₂ substrate as the back gate, we analyzed the transport properties of the device and the dependence on the pressure and on the electron bombardment. We demonstrate herein that low energy irradiation is detrimental to the transistor current capability, resulting in an increase in contact resistance and a reduction in carrier mobility, even at electron doses as low as 30 e-/nm². We also show that irradiated devices recover their pristine state after few repeated electrical measurements.
CNR-SPIN Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy. filippo.giubileo@spin.cnr.it.
Filippo
F
Giubileo
CNR-SPIN Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy. nadia.martucciello@spin.cnr.it.|Dipartimento di Fisica, Università di Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy. nadia.martucciello@spin.cnr.it.
Antonio
A
Di Bartolomeo
CNR-SPIN Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy.
Nadia
N
Martucciello
CNR-SPIN Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy. dibant@sa.infn.it.|Dipartimento di Fisica, Università di Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy. dibant@sa.infn.it.
Francesco
F
Romeo
Dipartimento di Fisica, Università di Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy. fromeo@sa.infn.it.
Laura
L
Iemmo
CNR-SPIN Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy. promano@unisannio.it.|Dipartimento di Scienze e Tecnologie, Università del Sannio, via Port'Arsa 11, 82100 Benevento, Italy. promano@unisannio.it.
Paola
P
Romano
Dipartimento di Scienze Fisiche e Chimiche, Università dell'Aquila, Via Vetoio, 67100 L'Aquila, Italy. maurizio.passacantando@aquila.infn.it.
Maurizio
M
Passacantando
contact resistance; electron irradiation; field-effect transistor; graphene