The Influence of Dopants on the Structural and Optical Properties of SnO2 Thin Films Deposited by PLD for Gas Sensor Application

Abstract

This study investigated the effects of different dopants (Mn, Cu, and Sb) on the characterization of SnO₂ thin films prepared by the pulsed laser deposition (PLD) technique. The pure and doped powders were prepared by the sol-gel technique and sintered at 600 оC for two hours. Structural analysis revealed a tetragonal structure in SnO2, and the addition of dopants induced lattice strain and increased dislocation density, thereby enhancing the number of active sites available for gas interactions. The morphology analysis revealed that the particles were uniformly distributed in the films and were almost spherical in shape. Optical measurements demonstrated a bandgap change, which decreased with doping from 3.83 eV to 2.8 eV. The higher sensitivity toward 50 ppm NO2 at 100°C operating temperature was 41.6% for the film doped with Sb, compared with films doped with Mn and Cu (25% and 24%). The results showed the different impacts of different dopants in enhancing the structural and optical properties of SnO2 thin films, which affect the sensor sensitivity toward NO2 gas.