Alharbi, Seham R.Qasrawi, Atef FayezGaabour, Laila H.2025-04-172025-04-172025Alharbi, S. R., Qasrawi, A. F., & Gaabour, L. H. (2025). Barium Oxide Thin Films Designed as Electro‐Optical Gigahertz/Terahertz Filters. Crystal Research and Technology, 2400212.0232-13001521-4079http://dx.doi.org/10.1002/crat.202400212https://hdl.handle.net/20.500.12713/6163Herein barium oxide thin films are studied as a promising electro-optical system. The deposited films exhibited a polycrystalline tetragonal structure and are composed of a mixture of BaO and BaO2. The p-type films are highly transparent (80%) with an energy band gap of 3.55 eV containing exponential band tails of widths of 1.22 eV. Analyses using the Drude-Lorentz model demonstrated the films suitability for nonlinear optical applications, with optical conductivity parameters revealing a scattering time constant in the range of 0.4-1.8 fs, a free hole concentration of 1018-1019 cm-3 and drift mobility values of 0.70-3.16 cm2 Vs-1. Terahertz cutoff frequency spectra calculations indicated the films capability as efficient terahertz band filters with a cutoff frequency range of 3.2-193.0 THz. Additionally, the nonlinear third-order optical susceptibility increased with decreasing incident photon energy. Applying an AC signal with a driving frequency of 0.01-1.40 GHz across the terminals of Yb/BaO/Ag devices revealed a high cutoff frequency (approximate to 9 GHz) in the microwave frequency domain. These properties highlight the potential of BaO films as nonlinear optical filters and microwave waveguides, positioning them as candidates for gigahertz/terahertz technology applications.eninfo:eu-repo/semantics/closedAccessBarium OxideDielectricGigahertzNonlinear OpticsTerahertzArticleWOS:0014401581000012-s2.0-85218681935Q310.1002/crat.202400212Q3