Universal mobility characteristics of graphene originating from charge scattering by ionised impurities

Abstract

Pristine graphene and graphene-based heterostructures can exhibit exceptionally high electron mobility if their surface contains few electron-scattering impurities. Mobility directly influences electrical conductivity and its dependence on the carrier density. But linking these key transport parameters remains a challenging task for both theorists and experimentalists. Here, we report numerical and analytical models of carrier transport in graphene, which reveal a universal connection between graphene’s carrier mobility and the variation of its electrical conductivity with carrier density. Our model of graphene conductivity is based on a convolution of carrier density and its uncertainty, which is verified by numerical solution of the Boltzmann transport equation including the effects of charged impurity scattering and optical phonons on the carrier mobility. This model reproduces, explains, and unifies experimental mobility and conductivity data from a wide range of samples and provides a way to predict a priori all key transport parameters of graphene devices. Our results open a route for controlling the transport properties of graphene by doping and for engineering the properties of 2D materials and heterostructures.

Light‐Induced Stark Effect and Reversible Photoluminescence Quenching in Inorganic Perovskite Nanocrystals

“…To investigate further this effect, we use graphene field effect transistor (FET) devices decorated with a layer of perovskite NCs. [ 7,31 ] Interestingly, we find that the power dependence of the photocurrent ( I ph ) of these devices is similar to that observed in the optical studies. The photocurrent depends on power as I ph ≈ P β , leading to a P ‐dependent photoresponsivity and β ≈ 0.4 (Figure 4c).…”

Nonlinear intensity dependence of terahertz edge photocurrents in graphene

“…Further increase of the Fermi energy will result in decrease of the current magnitude if the relaxation times get shorter, see, e.g., Refs. [38,39,[64][65][66][67]. Figures 3(b) and 4(b) show that in the vicinity of the CNP, at which J Dr 1 reduces and changes its sign, the photogalvanic cur-rent due to direct inter-band transitions dominates the total current.…”

3D Nickel Skeletons as Ultrabroadband Terahertz Absorbers

“…Terahertz (THz) waves located at the special frequency range of 0.1–10 THz on electromagnetic wave spectrum possess various excellent properties, visualizing the formation of the basis for future intelligent perception and imaging, [ 1–3 ] the next‐generation high‐speed wireless communications, [ 4–7 ] and so on. Rapid progresses on developing high‐energy THz sources, [ 8,9 ] ultrasensitive detectors, [ 10–13 ] and various functional devices [ 14–19 ] enable THz technologies to walk out from laboratories to serve significant strategic needs possible. Among numerous important demands, THz radars and communication [ 4–7 ] are one of most likely to be wide‐spread applied soon.…”