Structural, Magnetic and Gas Sensing Activity of Pure and Cr Doped In₂O₃ Thin Films Grown by Pulsed Laser Deposition

• Main Authors: Kamatam Hari Prasad, Karuppiah Deva Arun Kumar, Paolo Mele, Arulanandam Jegatha Christy, Kugalur Venkidusamy Gunavathy, Sultan Alomairy, Mohammed Sultan Al-Buriahi
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Coatings
• Subjects: In₂O₃/In₂O₃:Cr thin films; XPS; magnetization property; NH₃ sensor
• Online Access: https://www.mdpi.com/2079-6412/11/5/588

Pure In₂O₃ and 6% Cr-doped In₂O₃ thin films were prepared on a silicon (Si) substrate by pulsed laser deposition technique. The obtained In₂O₃/In₂O₃: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 <i>I</i>a-3. The SEM analysis showed the formation of agglomerated spherical shape morphology with the decreased average grain size for Cr doped In₂O₃ thin film compared to pure In₂O₃ film. It is observed that the Cr doped In₂O₃ 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 In₂O₃ 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 In₂O₃ film. NH₃ gas sensing studies was also carried out at room temperature for both pure and Cr doped In₂O₃ films, and the obtained higher sensitivity is 182% for Cr doped In₂O_3, which is about nine times higher than for the pure In₂O₃ film due to the presence of defects on the doped film surface.