Cerium oxide thin film growth using pulsed electron deposition method
Thesis Type: Postgraduate
Institution Of The Thesis: Ataturk University, Fen Bilimleri Enstitüsü, Nanobilim ve Nanomühendislik Anabilim Dalı, Turkey
Approval Date: 2024
Thesis Language: English
Student: THEKRA ABDELQADER RADWAN ALQUTAMY
Supervisor: Mustafa Tolga Yurtcan
Open Archive Collection: AVESIS Open Access Collection
Abstract:This study aims to investigate the growth and characterization of cerium oxide thin films on LaAlO3 substrates, which have a close lattice match with CeO2. The research focuses on determining the optimal growth temperature and evaluating the surface quality and crystallinity of the films for potential applications in catalysis, biomedical fields, and microelectronics. Method: Thin films of cerium oxide were deposited on LaAlO3 substrates using pulsed electron deposition at temperatures ranging from ambient to 600 °C, with increments of 100 °C. A CeO2 target, previously prepared, was used for deposition in an environment of 10 mTorr pressure with 99.999% purity oxygen gas. The ablation process was driven by an electron source operating at 15 keV. Various analytical techniques were employed, including X-ray photoelectron spectroscopy (XPS) for elemental analysis, grazing incidence X-ray diffraction (GIXRD) for phase identification, and surface characterization using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Findings: XPS analysis confirmed the presence of only cerium and oxygen in the deposited films. GIXRD results revealed that the samples predominantly exhibited a high-intensity peak corresponding to Ce2O3. Detailed GIXRD analysis showed the formation of three different cerium oxide phases with very low intensities: CeO2, Ce2O3, and Ce7O12. SEM and AFM analyses indicated that the sample deposited at 200 °C and annealed at 15 Torr exhibited the smoothest surface, essential for reducing light scattering and improving device efficiency in applications such as microelectronics and photonics. Results: The optimal growth temperature for achieving the best crystallinity of Ce2O3 was found to be 300 °C. The smoothest surface was obtained for films deposited at 200 °C and annealed at 15 Torr. Conversely, placing the substrate perpendicular to the target's normal or annealing at 30 Torr reduced the quality of the thin films. The study concludes that these cerium oxide thin films, with their nano-smooth surfaces, are suitable for various applications, particularly in areas requiring high surface quality and uniformity. Keywords: cerium oxide, CeO2, Ce2O3, Ce7O12, thin film, LaAlO3 (LAO), pulsed electron deposition, PED. August 2024, 72 pages doldurulacaktır"