Highly Sensitive Gr/Si Hetero Device for DNA Detection via Field-Effect Tunable Schottky Barrier

In this study, we present a highly sensitive graphene-based hetero device designed for the detection of target DNA sequences. The core structure of the device comprises an N-type silicon substrate overlaid with a graphene layer, whose quality is confirmed by Raman spectroscopy data showing a 2D/G peak ratio of 1.76. The graphene surface is bio-functionalized by immobilizing antibodies specifically tailored to capture target DNA sequences. The K3 peptide is adsorbed onto the graphene surface through π-π stacking interactions, enhancing the bio-functionalization process. Upon the introduction of the dCas9-E3 protein, significant changes are observed, demonstrating the high sensitivity of the device to biomolecular interactions.<br/> <br/>The device functions as a field-effect tunable Schottky barrier, where the field effect is utilized to modulate the Schottky barrier height, enhancing the sensitivity and selectivity of the device. Further performance analysis includes I-V measurements conducted at 3V under varying conditions. The device demonstrates its capability to operate effectively even at low analyte concentrations, achieving a current response of up to 500% at 100 pM target DNA in reverse bias, underscoring its high sensitivity and efficacy.<br/> <br/>Measurement data reveal distinct electrical characteristics when exposed to different concentrations of target DNA, specifically at 10 nM and 100 nM. The device shows a marked increase in current response proportional to the DNA concentration. These results indicate that the device can reliably detect varying levels of DNA, making it suitable for applications requiring precise quantification.<br/> <br/>Comparative studies with existing literature highlight the superior detection sensitivity of our graphene-based hetero device. The device's Schottky barrier measurements before and after the introduction of target DNA further illustrate its efficiency and reliability. The integration of encapsulation and PCB board connection enhances the device's robustness and practical applicability, ensuring stable operation in various environmental conditions.<br/> <br/>Our graphene-based hetero device offers a robust and highly sensitive platform for detecting target DNA sequences. By leveraging the unique electrical properties of graphene, π-π stacking interactions for bio-functionalization, and field-effect modulation of the Schottky barrier, we have developed a highly responsive and reliable sensor. Our graphene biosensor is promising as a platform for advanced semiconductor applications, enabling highly sensitive and precise electronic biosensing technologies.