Computational Study on the Electrical Behavior of Silicon Nanowire Memristive Biosensors

Abstract

Abstract-In this paper, a complete study is carried out investigating the relationship between the biosensing and the electrical characteristics of freestanding two-terminal Schottky-barrier silicon nanowires. This paper successfully reproduces computationally the electrical behavior obtained experimentally from the nanowire devices before and after the surface biomodification. Throughout modeling and simulations, this paper confirms that the experimental results obtained from the electrical characterization of bare two-terminal Schottky-barrier silicon nanowires present current-to-voltage characteristics fully equivalent to that of a pure memristor device, according to the literature. Furthermore, this paper shows that the voltage gap appearing in the current-to-voltage characteristics for nanowires with biomodified surface is related to capacitive effects due to minority carriers in the nanowire and it is also indicated that those effects are strongly affected by the concentration of antigens uptaken on the device surface. Overall, this paper confirms the implication of the memristive effect for biosensing applications and therefore, demonstrates the memristive biosensors.

Resistance impact by long connections on electrical behavior of integrated Memristive Biosensors

“…In previous work [11], equivalent circuits have been designed using CADENCE OrCAD consisting of a memristor model in combination with analog circuit elements connected in series and in parallel. The suggested equivalent circuits targeted at emulating the electric response of the two-terminal, Schottky-barrier silicon nanowire devices that exhibit memristive behavior in their electrical response, before -Memristive Devices-as well as after the bio-modification with antibodies -Memristive Biosensors-.…”

“…These two barriers are modeling both Schottky junctions at the ends of the wire as well as excess capacitances [11].…”

“…In order to investigate the impact of the Al lines on the electrical response of the Memristive Biosensors and, consequently, at the efficiency of the bio-detection method, the equivalent circuits in [11] are accordingly modified to include the introduction of the Al lines.…”

“…Simulations are implemented for the modified equivalent circuits of Memristive Device as well as for the Memristive Biosensor shown in Fig.3, under a sinusoidal input voltage, keeping the same input values parameters [11]. It is worth mentioning that these parameters are accordingly selected to match the experimental values of the conductivity [4], [5].…”

“…Therefore, Al lines for enabling the electrical readout are fabricated and integrated to the nanofabricated devices. In addition a computational study is carried out via proper modification of the circuit suggested in [11] aiming at the investigation of the impact that the introduction of additional Al lines brings to the electrical response of the physical system. The present study investigates the limits introduced by long connections in integrated Memristive Biosensor platforms in order to outline new possibilities for the integration of readout circuits that consequently allow the development of more complex platforms.…”