Exploration of sensitivity limit for graphene magnetic sensors

Operation of graphene magnetic field sensors near the charge neutrality point

“…Since the puddles are larger than the mean free path, the conductivities of individual puddles can be described by drift-diffusion 21 , and the transport involves a longer effective path-length and additional scattering (higher resistance). Thus, although puddles complicate the physical picture at the CNP and modify the effective transport parameters, the twochannel model still provides a useful approximation and has been used successfully for the study of graphene sensors by several groups 3,12,19 .…”

“…raphene is a promising material for magnetic field sensors because of its fundamental advantages of high carrier mobility, low sheet carrier density and weak temperature dependence [1][2][3][4][5] , and its practical advantages of simple and low-cost fabrication processes [5][6][7][8][9] . Studies of graphene for both magnetoresistance (MR) [10][11][12] and Hall sensors 2,3,13 have demonstrated performance outpacing traditional magnetic sensors based on semiconductors. For example, a large MR of~2000% at 9 T has been demonstrated in multilayer graphene on hexagonal boron nitride (h-BN) 12 .…”

“…This record value was achieved in a structure comprised of exfoliated graphene and h-BN stacks designed for high mobility. S I values in the range of about 1000-3000 VA −1 T −1 have been reported for more practical structures based on chemical vapor deposition (CVD) deposited graphene transferred onto various insulators, including exfoliated h-BN 2 , CVD h-BN 6 , and SiO 2 3,5 . Advanced "encapsulated" designs based on an all-CVD h-BN/graphene/h-BN sandwich structure have also been reported 8 , but have been limited thus far to about 100 VA −1 T −1 due to high carrier densities, emphasizing the importance of obtaining low carrier density, in addition to high mobility, for high sensitivity.…”

Flexible Hall sensors based on graphene

“…[18][19][20] So far, different graphene based Hall sensors exploiting the excellent electronic properties have been realized on rigid silicon based substrates, however the excellent flexibility of graphene has not been utilized in these devices. [21][22][23] Here, we present the fabrication and characterization of thin and flexible Hall sensors based on graphene that show a sensitivity significantly above that of state-of-the-art flexible Hall sensors and similar to silicon CMOS based Hall sensors in combination with excellent flexibility.…”

Sensitivity enhancement of graphene Hall sensors modified by single-molecule magnets at room temperature

“…The Hall sensors with high sensitivity can detect magnetic eld with high signal-noise ratio and thus reduce the cost of amplications. 23,32 The absolute sensitivity (S A ) of GHEs is dened as the ratio of Hall voltage and external magnetic eld, 19,24…”