Biosensors have various applications especially in medical diagnosis. In this paper, nanotube junctionless transistor is employed for label-free detection of biomolecules. The proposed device works based on dielectric modulated principle. In this transistor, the gate vo More
Biosensors have various applications especially in medical diagnosis. In this paper, nanotube junctionless transistor is employed for label-free detection of biomolecules. The proposed device works based on dielectric modulated principle. In this transistor, the gate voltage is responsible for controlling the drain current and in case of gate capacitance variation, the drain current can be modulated. A nanogap is embedded in the gate insulator region for immobilization of biomolecules. Since each individual biomolecule has its specific dielectric constant, the accumulation of different biomolecule in the nanogap changes the dielectric constant of the nanogap, which eventually leads to the variation of gate capacitance and the drain current. Threshold voltage variation and drain current modulation are considered as two measures for detecting biomolecules and determining the biosensor’s sensitivity. The proposed device has two internal and external gates with low static power consumption as well as simpler low temperature fabrication process. One of the main advantages of the proposed device is its high selectivity and sensitivity, especially for biomolecules with low dielectric constant. Impact of critical physical and structural design parameters on the operation of the biosensor are thoroughly investigated. Gate workfunction and channel doping density are two critical parameters that affect the sensitivity of the biosensor and as a consequence, optimum values should be determined for them. Due to the low power consumption and high sensitivity, this sensor can be considered as a potential candidate for applications in nanoscale regime.
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