Abstract

${\mathrm{Mg}}_{1\text{-}y}{\mathrm{Ca}}_y$ ($0.03\le y\le 0.17$) alloy thin films covered with thin Pd were hydrogenated using 4% ${\mathrm{H}}_2$ in Ar under atmospheric pressure at room temperature. The complex dielectric functions ($\epsilon ={\epsilon }_1+i{\epsilon }_2$) in the range of 0.75 to $5.0\mathrm{eV}$ of these hydrides were evaluated with spectroscopic ellipsometry. The imaginary part of the dielectric function ${\epsilon }_2$ was composed of one Drude and three Lorentz oscillator terms whose peak positions were about $1.2\mathrm{eV}$ ($L_1$), $2.8\mathrm{eV}$ ($L_2$), and $5.2\mathrm{eV}$ ($L_3$). The $L_3$ term observed in all hydrides is attributed to optical absorption of ${\mathrm{MgH}}_2$ with $E_g=5.16\mathrm{eV}$. The Drude term, which may be due to unhydrogenated Mg-metal, was observed in the hydrides with a low Ca composition y of less than 0.04. The $L_1$ term was observed in the hydrides with a Ca composition of more than 0.05, while the $L_2$ term was observed for more than 0.11. These $L_1$ and $L_2$ terms were estimated from a variation with hydrogenation of ellipsometric angle Ψ which is due to optical absorption of ${\mathrm{CaH}}_{2\text{-}\alpha }$ ($L_1$) and ${\mathrm{MgCaH}}_{3.72}$ ($L_2$).

© 2011 Optical Society of America

Parametric formulation of the dielectric function of palladium and palladium hydride thin films

William E. Vargas, Daniel E. Azofeifa, Neville Clark, Hugo Solis, Felipe Montealegre, and Michael Cambronero
Appl. Opt. 53(24) 5294-5306 (2014)

Optically addressing interaction of Mg/MgO plasmonic systems with hydrogen

Yael Gutierrez, Maria M. Giangregorio, Fabio Palumbo, April S. Brown, Fernando Moreno, and Maria Losurdo
Opt. Express 27(4) A197-A205 (2019)

Optimizing magnesium thin films for optical switching applications: rules and recipes

Julian Karst, Mario Hentschel, Florian Sterl, Heiko Linnenbank, Monika Ubl, and Harald Giessen
Opt. Mater. Express 10(6) 1346-1362 (2020)

Highly switchable absorption in a metal hydride device using a near-zero-index substrate

Kevin J. Palm, Lisa J. Krayer, and Jeremy N. Munday
Opt. Express 30(12) 21977-21989 (2022)

Dielectric function of vanadium oxide thin films by thermal annealing

Adolf Canillas, Frank Güell, Oriol Arteaga, Paulina R. Martínez-Alanis, Michel Vergnat, Hervé Rinnert, and Blas Garrido
Appl. Opt. 60(15) 4477-4484 (2021)