Manufacturing gas sensors based on ZnO and silicon

Fecha: 11 de Mayo de 2023.
Hora: 12:00 a 13:00.
Lugar: Aula A22 de la Facultad de Ciencias.

Ponente: Siham Mebarek (University of Science and Technology of Oran Mohamed Boudiaf). 

Organiza: Grupo de Física de Fluidos y Biocoloides del Departamento de Física Aplicada de la UGR.

ZnO@Si gas sensors work on the principle of falling resistance of a ZnO layer deposited on a silicon substrate upon adsorption of gasses, such as alcohol or carbon monoxide. The latter is a health problem in winter in my country, Algeria. Previous attempts in our lab required significant heating of the sensors, consuming a few watts during the measuring process. In order to reduce the power consumption, we plan to miniaturize the sensors by using conventional lithography masks and etching of the silicon substrates. Thus, on one side of the sensor we will deposit the ZnO layer and on the opposite side of the sensor we will deposit the resistors to locally heat the sensor. We also need miniaturized contacts to measure the resistance of the ZnO layer. The final goal is to master all of these processes in our lab in Algeria to produce multiple sensors on a single silicon wafer. Thanks to an Erasmus+ research stay, currently I am working with Dr. Miguel Angel Fernandez-Rodriguez to adapt the soft colloidal lithography technique to produce nanostructured layers of ZnO nanoparticles. In this technique we use microgels that we self-assemble at water/air interfaces and deposit on silicon substrates. The deposited microgel monolayers act as negative masks for the electrostatic adsorption of ZnO nanoparticles. Based on previous publications, we believe that nanostructuring will enhance the efficiency of the gas sensors.