| AVS 66th International Symposium & Exhibition | |
| Spectroscopic Ellipsometry Focus Topic | Wednesday Sessions |
| Session EL+EM-WeA |
| Session: | Spectroscopic Ellipsometry: Novel Applications and Theoretical Approaches |
| Presenter: | Alyssa Mock, U.S. Naval Research Laboratory |
| Authors: | A. Mock, U.S. Naval Research Laboratory S. Knight, University of Nebraska-Lincoln M. Hilfiker, University of Nebraska-Lincoln V. Darakchieva, Linkoping University, Sweden A. Papamichail, Linkoping University, Sweden R. Korlacki, University of Nebraska-Lincoln M.J. Tadjer, U.S. Naval Research Laboratory Z. Galazka, Leibniz-Institut für Kristallzüchtung, Germany G. Wagner, Leibniz-Institut für Kristallzüchtung, Germany N. Blumenschein, North Carolina State University A. Kuramata, Novel Crystal Technology, Inc., Japan K. Goto, Tokyo University of Agriculture and Technology, Japan H. Murakami, Tokyo University of Agriculture and Technology, Japan Y. Kumagai, Tokyo University of Agriculture and Technology, Japan M. Higashiwaki, National Institute of Information and Communications Technology, Japan A. Mauze, University of California Santa Barbara Y. Zhang, University of California Santa Barbara J.S. Speck, University of California Santa Barbara M. Schubert, University of Nebraska-Lincoln, Linköping University, Sweden, Leibniz Institute of Polymer Research Dresden, Germany |
| Correspondent: | Click to Email |
We discuss the analysis of the dielectric function tensor for monoclinic metal oxides obtained from generalized spectroscopic ellipsometry. We investigate the potential high-power device material gallium oxide and derive dispersions of transverse, longitudinal and plasmon coupled modes [M. Schubert et al., Phys. Rev. B 93, 125209 (1-18) (2016); Editors’ Suggestion] and the band-to-band transitions and excitons along with their eigenvectors [A. Mock et al., Phys. Rev. B 96, 245205 (1-12) (2017)]. Additionally, we show that this technique can fully explain the unusual ordering of optical phonon mode pairs which is observed in beta-Ga2O3 [M. Schubert, A. Mock et al. Phys. Rev. B 99, 041201(R) (2019)] as well as their dependency on free charge carrier concentrations. [M. Schubert, A. Mock et al. Appl. Phys. Lett. 114, 102102 (2019) – Editor’s Pick]. We apply this technique also for the identification of transverse and longitudinal phonons in scintillator material cadmium tungstate [A. Mock et al., Phys. Rev. B 95, 165202 (1-15) (2017)], and then further extend our methodology for analysis of the dielectric and inverse dielectric tensor for transverse and longitudinal phonon mode dispersion characterization in high-power laser material yttrium orthosilicate [A. Mock et al., Phys. Rev. B, 97 165203 (1-17) (2018)].
We apply our technique to investigate the effective electron mass tensor using optical Hall effect measurements [S. Knight, A. Mock et al., Appl. Phys. Lett. 112, 012103 (2018); Editors’ Pick], the temperature dependence of band-to-band transitions energies [A. Mock et al., Appl. Phys. Lett. 112, 041905 (2018)], and the effects of aluminum alloying concentration onto the band-to-band transition energies [M. Hilfiker, A. Mock et al. Appl. Phys. Lett. (Under Review)]. We further apply our technique to epitaxial layers of beta-phase gallium oxide and discuss the relationship between the X-ray diffraction measured strains with respect to the optically determined shifts in transverse optical phonon modes as compared to the bulk material. Understanding of the stress and strain relationship to properties in monoclinic materials will help facilitate better control of material properties for engineering next generation power devices based on beta-Ga2O3.