Structural, magnetic and gas sensing activity of pure and cr doped in₂ o₃ thin films grown by pulsed laser deposition

Pure In₂ O₃ and 6% Cr-doped In₂ O₃ thin films were prepared on a silicon (Si) substrate by pulsed laser deposition technique. The obtained In₂ O₃ /In₂ O₃:Cr thin films structural, morphological, optical, magnetic and gas sensing properties were briefly investigated. The X-ray diffraction results confirmed that the grown thin films are in single-phase cubic bixbyte structure with space group Ia-3. The SEM analysis showed the formation of agglomerated spherical shape morphology with the decreased average grain size for Cr doped In₂ O₃ thin film compared to pure In₂ O₃ film. It is observed that the Cr doped In₂ O₃ thin film shows the lower band gap energy and that the corresponding transmittance is around 80%. The X-ray photoelectron spectroscopy measurements revealed that the presence of oxygen vacancy in the doped In₂ O₃ film. These oxygen defects could play a significant role to enhance the sensing performance towards chemical species. In the magnetic hysteresis loop, it is clear that the prepared films confirm the ferromagnetic behaviour and the maximum saturation value of 39 emu/cc for Cr doped In₂ O₃ film. NH₃ gas sensing studies was also carried out at room temperature for both pure and Cr doped In₂ O₃ films, and the obtained higher sensitivity is 182% for Cr doped In₂ O_3, which is about nine times higher than for the pure In₂ O₃ film due to the presence of defects on the doped film surface.