Macroscopic acoustoelectric charge transport in graphene

Abstract

We demonstrate macroscopic acoustoelectric transport in graphene, transferred onto piezoelectric lithium niobate substrates, between electrodes up to 500 μm apart. Using double finger interdigital transducers we have characterised the acoustoelectric current as a function of both surface acoustic wave intensity and frequency. The results are consistent with a relatively simple classical relaxation model, in which the acoustoelectric current is proportional to both the surface acoustic wave intensity and the attenuation of the wave caused by the charge transport.

Controlling the properties of surface acoustic waves using graphene

“…The value of gate capacitance, ≈ 1 μF/cm 2 , was taken from that calculated by Chakraborty et al [31] for a similar configuration. The values of electron and hole mobility obtained, approximately 5 cm 2 /(V·s), are much smaller than those typical for CVD graphene on Si/SiO 2 , but are consistent with the values of mobility we have previously extracted from SAW measurements [26,27] on similar graphene/lithium niobate hybrids. The measured SAW amplitude and phase at 11 MHz from the same device are plotted as a function of applied gate bias in Figs.…”

“…For example, SAW devices that are responsive to hydrogen and carbon monoxide [19], and moisture [20][21][22][23] have been reported. Acoustic charge transport has also very recently been reported in graphene [24,25], and we have investigated it in monolayer graphene, produced by chemical vapor deposition (CVD), and transferred onto lithium niobate SAW devices, both at room temperature [26], at low temperature [27], and under illumination [28].…”

Acoustoelectric photoresponse in graphene

“…At both SAW frequencies, negative I ae was observed, corresponding to the net transport of electrons by the SAW, suggesting that the sample was ndoped. This is in contrast to previous measurements 21 where the acoustoelectric current corresponded to the net transport of holes. In the current case, the vacuum chamber, with the sample mounted inside, was pumped continuously for a number of weeks before measurements began.…”

“…[14][15][16][17][18] Acoustic charge transport has very recently been reported in graphene, 19,20 and we have investigated it in monolayer graphene, produced by chemical vapour deposition (CVD), transferred onto lithium niobate SAW devices, both at room temperature 21 and low temperature. 22 In this paper, we show that illumination of the same devices, using blue (450 nm) and red (735 nm) light-emitting diodes (LEDs), causes an increase in the acoustoelectric current which is much larger than the associated change in the conductivity of the graphene.…”

Multilayer-graphene-based amplifier of surface acoustic waves

“…Owing to the form of the spectrum, there are many features defining the charge transport, 7,8 in particular, the high-current transport. [9][10][11] A series of related studies was performed recently to understand (i) the conductivity of graphene and its carrier dynamics, [12][13][14][15][16][17] (ii) plasmonic effects, [18][19][20][21] (iii) the own phonon generation by the carrier current, [22][23][24][25] (iv) the interaction between graphene electrons and SAWs, [26][27][28][29] and (v) sandwich-like "graphene-piezoelectric" structures, which allow one to create a new class of opto-acousto-electronic devices. [30][31][32][33][34] Nevertheless, the problem of modeling SAW amplification in graphene-based SAW amplifiers has not been studied systematically to date.…”