Epitaxial growth of engineered metals for mid-infrared plasmonics

The authors demonstrate the ability of high-quality epitaxial InAs films to be used as wavelength-flexible, low-loss, engineered plasmonic metals across the mid-infrared spectral range. Films are grown by molecular beam epitaxy and characterized by Hall effect measurements, atomic force microscopy, and infrared reflection and transmission spectroscopy. The losses of our plasmonic material are studied as a function of InAs doping density, growth rate, buffer layer type, and substrate type. High growth rates are shown to be integral to obtaining films with low losses and doping densities approaching 1 x 10(20) cm(-3). (C) 2013 American Vacuum Society.