Electron transport tuning of graphene by helium ion irradiation

Abstract

This article reviews charge carrier transport phenomena in single-layer graphene, which generates crystalline defects through helium-ion-beam irradiation using a helium-ion microscope. Crystalline defects act as electron scatterers, and the conductivity decays drastically with increase in ion dose. Real-time conductivity monitoring during ion beam scans over the graphene surface is also presented. Negative magnetoresistance is observed in defective graphene in cryogenic measurements under magnetic fields, suggesting that strong localisation occurred in this two-dimensional electron system, which survived even at room temperature. The localised state also contributes to inducing a transport gap around the Dirac point, where the density of states is at its minimum, and it enables field-effect control of the carrier transport by tuning the carrier density. The fabrication and operation of field-effect transistors with defective graphene channels are also demonstrated.

Magnetic field imaging by hBN quantum sensor nanoarray

“…Using Orion Plus HIM (Carl Zeiss Microscopy LLC, Peabody, MA, USA), a helium ion beam with a nominal width of 0.3 nm is raster scanned at 7 nm intervals to homogeneously dose in each spot. 39 We set the acceleration voltage to 30 keV and the average dose for each spot to 10 15 cm −2 . The acceleration voltage is the same as in previous studies, 37,40 and He + is expected to pass through the hBN flake after producing V − B .…”

Recent progresses on ion beam irradiation induced structure and performance modulation of two-dimensional materials

“…10, the FETs based on the ion irradiation-synthesized graphene have excellent performance. Recently, Nakaharai et al 213 reviewed the manipulation of electron transport in graphene by He + ion irradiation, demonstrating the use of defective graphene in the fabrication and operation of FETs. Meanwhile, graphene-based FETs are also capable of detecting particle irradiation by measuring the perturbations in the local electric field.…”

Spectromicroscopy Study of Induced Defects in Ion-Bombarded Highly Aligned Carbon Nanotubes

“…Thus, the development of methods capable of controlling the amount and type of defects in MWCNTs is highly desirable, both for addressing the defect origin and for exploiting their properties to engineer the system characteristics. Among such methods, the use of heavy ions cause surface roughening and the removal of carbon atoms, leading to changes in the surface structure and properties of the nanotubes [ 4 ]. On the other hand, implanting lighter ions can affect the chemical composition and electronic properties of the nanotubes [ 5 ].…”

“…Effects on CNTs upon ion irradiation can be compared with analogous studies on its basic constituent, graphene. Carbon [ 25 ], helium [ 4 ], hydrogen [ 26 ] and deuterium were irradiated on graphene to functionalize it and to observe the charge carrier transport phenomena, to produce defects that lead to engineering process [ 27 ] and to unveil the band gap opening [ 26 ], useful for optoelectronic properties.…”