@article{dfc2b798310f49398a96c6ca01c47809,
title = "The anisotropic quasi-static permittivity of single-crystal β -Ga2O3measured by terahertz spectroscopy",
abstract = "The quasi-static anisotropic permittivity parameters of electrically insulating beta gallium oxide (β-Ga2O3) were determined by terahertz spectroscopy. Polarization-resolved frequency domain spectroscopy in the spectral range from 200 GHz to 1 THz was carried out on bulk crystals along different orientations. Principal directions for permittivity were determined along crystallographic axes c and b and reciprocal lattice direction a*. No significant frequency dispersion in the real part of dielectric permittivity was observed in the measured spectral range. Our results are in excellent agreement with recent radio frequency capacitance measurements as well as with extrapolations from recent infrared measurements of phonon mode and high-frequency contributions and close the knowledge gap for these parameters in the terahertz spectral range. Our results are important for applications of β-Ga2O3 in high-frequency electronic devices.",
author = "Prashanth Gopalan and Sean Knight and Ashish Chanana and Megan Stokey and Praneeth Ranga and Scarpulla, {Michael A.} and Sriram Krishnamoorthy and Vanya Darakchieva and Zbigniew Galazka and Klaus Irmscher and Andreas Fiedler and Steve Blair and Mathias Schubert and Berardi Sensale-Rodriguez",
note = "Funding Information: This work was supported in part by the Air Force Office of Scientific Research under Award Nos. FA9550-18-1-0507, FA9550-18-1-0360, and FA9550-18-1-0332, by the National Science Foundation under Award Nos. DMR 1808715 and ECCS 1810096, by the National Science Foundation supported Nebraska Materials Research Science and Engineering Center under Award No. DMR 1420645, by the Swedish Governmental Agency for Innovation Systems (VINNOVA) under Competence Center Program Grant No. 2016-05190, Swedish Research Council VR Award No. 2016-00889, and Swedish Foundation for Strategic Research Grant Nos. RIF14-055 and EM16-0024, by the Knut and Alice Wallenbergs Foundation supported grant “Wide-bandgap semiconductors for next generation quantum components,” and by the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University, Faculty Grant SFO Mat LiU No. 2009-00971. This work was also partly performed in the framework of GraFOx, a Leibniz-Science Campus partially funded by the Leibniz Association, Germany. M.S. acknowledges the University of Nebraska Foundation and the J. A. Woollam Foundation for financial support. The authors thank John Blevins (Air Force Research Lab) for providing the synoptics (010) β-Ga2O3 bulk substrates used in the measurements. Publisher Copyright: {\textcopyright} 2020 Author(s).",
year = "2020",
month = dec,
day = "21",
doi = "10.1063/5.0031464",
language = "English (US)",
volume = "117",
journal = "Applied Physics Letters",
issn = "0003-6951",
publisher = "American Institute of Physics Publising LLC",
number = "25",
}