Ultrasensitive Real-Time Detection of Pb<sup>2+</sup> Ions Using g-C<sub>3</sub>N<sub>4</sub> Nanosheets
Nipun Sharma, Arun Kumar Sakthivel, Subbiah Alwarrapan, Ankur Gupta, Ahmed S. Razeen, Dharmraj Subhash Kotekar Patil, S. Tripathy, Mahesh Kumar
Abstract
The quick and easy monitoring of heavy metals in drinking water is utmost important due to their harmful effects on human health. In this work, a GaN-based high-electron-mobility transistor (HEMT) sensor has been fabricated using optical lithography and explored as a prospective sensor for the determination of trace Pb2+ ions present in the water. Graphitic carbon nitride (g-C3N4) was synthesized by a single-step combustion method. The g-C3N4 nanosheets were used to functionalize the gate area of the fabricated GaN HEMT sensor to investigate the presence of Pb2+ metal ions in water. The g-C3N4 functionalized sensor exhibited a sensitivity of around <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.46 \mu \text{A}$ </tex-math></inline-formula> /ppb with 0.32 ppb, as the limit of detection (LoD) is much below the international set standards. Moreover, the real-time measurements on lake water were performed using the developed GaN HEMT sensor to detect the presence of Pb2+ ions in real samples in a fast and ultrasensitive manner. We anticipate that the reported work will certainly serve as a proof-of-concept to develop heavy metal ion sensors.