Our research involves the experimental investigation of metal oxide thin films as active components for metamaterial and plasmonic devices. We are interested in transparent conducting oxides such as ITO, AZO, and GZO as low loss plasmonic materials. Their electrical and optical properties can be modified by doping and thus their plasma frequency can be tuned across a wide range of frequencies. We are also interested in phase-changing materials, such as VO2, with tunable electrical/optical/structural properties. The VO2 thin films are used as active elements for metamaterial-based tunable THz devices or as broadband THz sources. Other electronic oxides, such as ferroelectric, ferromagnetic, and multiferroic thin films, are also under investigation together with new applications in sensors and electronics. Thin films of these oxides are deposited by pulsed laser deposition. Materials characterization capabilities include XRD, AFM, SEM, TEM, ellipsometer (UV-IR), Hall Effect measurements, PPMS, and MPMS. Device fabrication facilities include conventional photolithographic process, e-beam lithography, ion-milling, reactive dry etching, and other tools available in the NRL Nanoscience Center.
Charipar NA, Kim H, et al: “Broadband terahertz generation using the semiconductor-metal transition in VO2”. AIP Advances 6: 015113, 2016
Kim H, et al: “Active terahertz metamaterials based on the phase transition of VO2 thin films.” Thin Solid Films 596: 45-50, 2015
Kim H, et al: “Optimization of Al-doped ZnO films for low loss plasmonic materials at telecommunication wavelengths.” Applied Physics Letters 102: 171103, 2013
Metal oxides; Thin films; Transparent conducting oxides; Vanadium dioxide; Phase changing materials; Plasmonic materials; Metamaterials; Multiferroic;