Van der Waals Integration of Tellurium Nanowires With Graphene Oxide for Performance-Enhanced Ion-Sensitive Field-Effect Transistors.

Nanowire bioelectronic sensors offer extraordinary sensitivity and real-time transduction, with silicon being the primary material for device realization. For all nanowire-based ion-sensitive field-effect transistors (ISFETs), direct electrolyte contact or passivation by amorphous dielectrics often introduces interfacial traps leading to instabilities, reduced capacitive control, and poor switching. In this work, we fabricated performance-enhanced ISFETs from ultrathin, highly crystalline tellurium nanowires (TeNW), which are known for their unique, quasi one-dimensional (1D) van der Waals structure. The TeNW networks were passivated with ultra-thin films of insulating graphene oxide (GO). This van der Waals integration enabled high-performance ISFET arrays, which exhibit strongly enhanced p-type field-effect characteristics, clearly outperforming TeNW ISFETs with direct electrolyte contact and those passivated by amorphous silicon dioxide. We account for this performance enhancement by a van der Waals interaction between the 1D TeNW and 2D GO. The resulting TeNW/GO-ISFETs demonstrate stable operation in phosphate-buffered saline, while exhibiting apparent pH sensitivities of up to 290 mV/pH, significantly exceeding the Nernstian limit as an effect of the van der Waals interaction. Our findings demonstrate that this van der Waals integration is a viable strategy for performance-enhanced tellurium ISFETs, paving the way for next-generation bioelectronics in healthcare diagnostics and environmental monitoring.