Gate Electrolyte Transistors: A Promising Approach for Heavy Metal Detection in Agriculture.

• Grant number: 24/14553-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: April 01, 2025
• End date: March 31, 2028
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Neri Alves
• Grantee: Vinicius Jessé Rodrigues de Oliveira Patzer
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

With population growth and the high demand for food production, agriculture faces significant sustainability challenges, with heavy metal contamination emerging as a serious global public health issue. In this context, there is a growing interest in developing sensors that can identify these contaminants in a sustainable and cost-effective manner. This project proposes the study of "Electrolyte-Gated Transistors" (EGTs) as sensors for heavy metals in aqueous solutions containing lead or cadmium, employing carbon nanotubes (CNT) deposited via Langmuir-Schaefer (LS) as electrodes and zinc oxide (ZnO) deposited via spray pyrolysis as a semiconductor-both of which are materials widely used in electrochemical sensors. The transistors will be fabricated and studied as sensors in two basic architectures, known as planar and vertical transistors. The project will also investigate devices related to these transistors, such as the Schottky diode, which is an active cell in a vertical transistor, and the metal-insulator-semiconductor (MIS) capacitor, which is the capacitive cell of a planar transistor. The development of CNT electrodes using LS is a novel approach and will allow for control over conductivity and morphology, which are crucial factors for the vertical EGT architecture, where the electrode should not shield the electric field in the vertical direction and must exhibit good electrical conductivity in the transverse direction. The study includes the characterization of CNT and ZnO thin films using optical, spectroscopic, and morphological techniques, as well as the electrical characterization of materials and devices using standard transistor measurements to determine their key parameters. The expected outcomes aim to contribute to the development of more efficient and sustainable technologies for detecting heavy metals in agriculture and sectors related to food and environmental safety.