A Master’s thesis in the Department of Physics has investigated the fabrication and characterization of Cr₂O₃₂/PSi hybrid thin films for gas sensor applications, with particular emphasis on detecting nitrogen dioxide (NO₂) and hydrogen sulfide (H₂S), two toxic gases that can pose significant risks to human health and the environment at elevated concentrations.
The thesis, entitled “Fabrication and Characterization of Cr₂O₃₂/PSi Thin Films for Gas Sensor Applications,” was prepared by Master’s student Nihad Khalid Ali Rahim under the supervision of Assistant Professor Dr. Ikhlas Hamim Shallal.
The study aimed to fabricate gas sensors based on the hybrid heterostructures (Al/Cr₂O₃/PSi/Si/Al) and (Al/Cr₂O₃₂/PSi/Si/Al). The research employed pure chromium(III) oxide (Cr₂O₃) thin films as well as films doped with titanium dioxide (TiO₂) at concentrations of 2%, 4%, 6%, and 8%, in order to investigate the influence of TiO₂ incorporation on the physical and sensing properties of the fabricated films.
The study involved the preparation of nanoparticles using the Pulsed Laser Ablation in Liquid (PLAL) technique, followed by the deposition of the prepared solutions onto porous silicon (PSi) substrates at a temperature of 400°C using the drop-casting method. These structures were subsequently employed in the fabrication of the hybrid gas-sensing devices.
The research also focused on characterizing the fabricated thin films and evaluating their gas-sensing performance at different operating temperatures, including room temperature (RT), 100°C, and 150°C. This approach was intended to identify suitable operating conditions and develop gas sensors with enhanced sensitivity and favorable sensing characteristics for the detection of toxic gases.
The study has important practical implications because it focuses on the development of advanced technologies for detecting nitrogen dioxide (NO₂) and hydrogen sulfide (H₂S), both of which can constitute serious health and environmental hazards when present at high concentrations. The development of sensitive and efficient gas sensors can contribute to environmental and industrial monitoring systems and enhance the early detection of hazardous gaseous pollutants.
The research directly supports United Nations Sustainable Development Goal 3 (SDG 3): Good Health and Well-Being, by contributing to the development of technologies capable of detecting toxic gases that may adversely affect human health. It also aligns with SDG 9: Industry, Innovation and Infrastructure, through its application of nanotechnology, pulsed laser ablation, thin-film engineering, and hybrid materials in the development of advanced sensing devices. Furthermore, the study is relevant to SDG 11: Sustainable Cities and Communities, as the developed gas-sensing technologies may potentially support air-quality monitoring and the detection of gaseous pollutants in urban and industrial environments.
The thesis examination committee was chaired by Professor Dr. Bushra Kadhim Hassoun, with Assistant Professor Dr. Hana Ibrahim Mohammed and Assistant Professor Dr. Widian Kadhim Abdul serving as committee members.
The research reflects the growing role of applied physics, nanotechnology, thin-film engineering, and hybrid materials in the development of advanced gas-sensing technologies. It highlights the potential of innovative material architectures to contribute to more efficient monitoring of hazardous gases and to support technological solutions for environmental and public-health challenges.
