ZnO/SnO2 Heterostructures: Microstructural Characterization and Sensor Performance Evaluation

• Grant number: 25/07284-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: June 30, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Luís Fernando da Silva
• Grantee: João Vitor Almas Francisco
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 22/02927-3 - Gas sensors based on n-type semiconductors operating at room temperature: investigation of their performance and mechanisms involved, AP.PNGP.PI

Abstract

In past decades, semiconducting metal oxides (MOXs) have been extensively investigated, attracting great attention due to their interesting applications in electronic devices, heterogeneous catalysis, gas sensors, and energy generation. Among the MOXs exhibiting potential properties as sensing layer, n-type semiconductors, more specifically ZnO and SnO2, stand out. Although a significant amount of work dedicated to the investigation of SnO2 and ZnO as sensing layer has been published, the enhancement of selectivity and their operation at temperatures closer to ambient remain the main challenges to be achieved. Different studies have shown that sensor performance is significantly influenced by the control of certain processing parameters (e.g. precursor source, treatment time and temperature, solution pH, and so on). In this context, this project aims to synthesize ZnO-SnO2 heterostructures by the hydrothermal method, aiming at their application as sensors of volatile organic compound (ethanol and acetone). The obtained sensing materials will be characterized by conventional techniques, such as X-ray diffractometry, electron microscopies, photoluminescence spectroscopy, and electrical measurements (DC and AC). The choice of the hydrothermal method is due to the feasibility of growing directly on the sensor platforms oriented ZnO structures exhibiting rod-like morphology. First of all, a study will be carried out on the influence of the time and temperature of hydrothermal treatment on the microstructural properties of the pure ZnO compound. After the optimization of such parameters, the next step of the project will consist of the decoration of the ZnO rods with SnO¿ nanoparticles (NPs) by spraying a colloidal suspension of SnO2 onto the rods. For this purpose, we will investigate the effect of different concentrations of SnO2 NPs on the microstructural and sensor properties of the obtained materials. At the end of the project, it is expected to obtain an efficient route for obtaining ZnO-SnO2 heterostructures showing potential as sensors of volatile organic compounds (VOCs) operating at temperatures close to room temperature. (AU)