Precision pH Sensing beyond the Nernst Limit with MoS<sub>2</sub>/WSe<sub>2</sub> Van der Waals Heterostructure Ion Sensitive Field Effect Transistors.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41686136.
- Also identified by DOI 10.1021/acsnano.5c15447.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Field-effect transistor (FET)-based sensors are widely investigated for label-free, real-time ion detection; however, their sensitivity is commonly limited by the Nernstian response (∼59 mV/pH). In this work, real-time pH sensing is demonstrated using a MoS<sub>2</sub> (top)/WSe<sub>2</sub> (bottom) van der Waals heterostructure ion-sensitive FET (ISFET), achieving a pH sensitivity of ∼441.3 mV/pH. The device incorporates a screening layer formed by interfacial and channel charges, along with engineered trap states, which leads to enhanced sensitivity while maintaining device scalability. The ultrascaled ISFET employs ∼15 nm Al<sub>2</sub>O<sub>3</sub> as the top dielectric, ∼30 nm HfO<sub>2</sub> as the back dielectric, and a few layers of MoS<sub>2</sub>/WSe<sub>2</sub> as the channel. The sensor shows a linear, stable, and repeatable response over a wide pH range, as verified through cycling measurements. Low-frequency noise analysis indicates a pH sensing resolution of 1.36 × 10<sup>-3</sup> pH. These results highlight the applicability of van der Waals heterostructure-based ISFETs for scalable and high-resolution biosensing applications.