Charge pumping technique to analyze the effect of intrinsically retained charges and extrinsically trapped charges in biomolecules by use of a nanogap embedded biotransistor

Charge pumping technique is investigated for label-free electrical biosensing using a nanogap-embedded biotransistor. Biomolecules immobilized in a nanogap provide additional trap states and charges in the gate dielectric. These two effects give rise to a change of the charge pumping current, which are analyzed by the aid of numerical simulations. To utilize the trap density of gate dielectric as a sensing parameter, proper amplitude of pulse should be applied for charge pumping to exclude the effect of intrinsically retained charges in biomolecules, thereby this proposed technique is available for detection of biomolecules regardless of retained charges.