Hall effect biosensors with ultraclean graphene film for improved sensitivity of label-free DNA detection

•The detection limit of graphene DNA sensors with ultraclean surface can achieve 1 pM.•The sensitivity of the devices is 5 times higher than that prepared by common PMMA transfer process.•The performance of the devices is 4 times better than liquid-gated FET decives.

The quality of graphene strongly affects the performance of graphene-based biosensors which are highly demanded for the sensitive and selective detection of biomolecules, such as DNA. This work reported a novel transfer process for preparing a residue-free graphene film using a thin gold supporting layer. A Hall effect device made of this gold-transferred graphene was demonstrated to significantly enhance the sensitivity (≈ 5 times) for hybridization detection, with a linear detection range of 1 pM to 100 nM for DNA target. Our findings provide an efficient method to boost the sensitivity of graphene-based biosensors for DNA recognition.

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