Graphene FETs with high and low mobilities have universal temperature-dependent properties

Abstract

We use phenomenological modelling and calculations of charge carrier scattering to investigate the dependence of the electrical resistivity, Ro, on gate voltage, Vg, for a series of monolayer graphene field effect transistors with mobilities, mu, ranging between 5,000 and 200,000 cm2/Vs at low-temperature. Our measurements over a wide range of temperatures from 4 K to 400 K can be fitted by the relation μ=4/eδnRo_max for all devices, where Ro_max is the resistivity maximum at the neutrality point and delta-n is an “uncertainty” in the bipolar carrier density, given by the full width at half maximum of the resistivity peak expressed in terms of n. This relation is consistent with thermal broadening of the carrier distribution and the presence of the disordered potential landscape consisting of so-called electron-hole puddles near the Dirac point. To demonstrate its utility, we combine this relation with linearised temperature-dependent Boltzmann transport calculations that include the effect of optical phonon scattering. This approach demonstrates the similarity in the temperature-dependent behaviour of carriers in different types of single layer graphene transistors with widely differing carrier mobilities. It can also account for the relative stability, over a wide temperature range, of the measured carrier mobility of each device.

Cu-Vapor-Assisted Growth of 2D SiO2 Flakes and As-Oriented Graphene Arrays

“…However, in this case, due to the high surface roughness of the as-produced SiO 2 , the contact resistance and uncertainty were all large. All of the above means that the formula μ = 4 / ( normale × δ n × ρ max ) may lead to the wrong mobility, in which ρ max refers to the peak resistivity at the neutrality point and δ n is an “uncertainty” in the bipolar carrier density . Therefore, we calculated the mobility in another convincing manner.…”

“…33 Although it is hard to obtain the intrinsic resistance in the Dirac point, we estimated it to be about 1 MΩ, which is much higher than 1−10 kΩ per square typically observed in other graphene-based FETs. 34 In addition, the measured mobility was negatively related to the width of the R(V g ) peak because the width corresponds to a degree of uncertainty of the bipolar carrier density around the Dirac point. Assuming low ohmic contacts, this uncertainty should be relatively small (<20%).…”

“…may lead to the wrong mobility, in which ρ max refers to the peak resistivity at the neutrality point and δn is an "uncertainty" in the bipolar carrier density. 34 Therefore, we calculated the mobility in another convincing manner. Because the FET works in a linear region, the following formula should be used to calculate the mobility.…”

Design of silicon-on-insulator field-effect transistor using graphene channel to improve short channel effects over conventional devices

“…The SS and I ON /I OFF ratio are affected by the GNR width. The impact of temperature on the mobility of GFET was researched by Gosling et al [30]. Studied the transit of charge carriers in monolayer graphene.…”

Recent advances in density functional theory approach for optoelectronics properties of graphene

“…Despite the surge in 2D materials, graphene stands out among them for having exceptional electronic, optical, and thermal properties [ 14 , 15 ]. It has very high carrier mobilities ( 200,000 ) [ [16] , [17] , [18] ], unusual linear dispersion around the Dirac point [ 19 , 20 ], ultrahigh thermal conductivities ( ) [ [21] , [22] , [23] ], room temperature ballistic carrier transport [ 24 , 25 ], large surface area (2630 ) [ [26] , [27] , [28] ], a Young's Modulus of 1 TPa [ 29 , 30 ], broadband optical absorbance (2.3%) [ [31] , [32] , [33] ], and a robust crystal structure, all of which reveal the material's high quality and suggest its prospects for future optoelectronic devices [ [34] , [35] , [36] ]. However, its use in optoelectronics is limited due to its zero bandgap and relatively poor structural tunability [ [37] , [38] , [39] ].…”