Optical constants of electron-beam evaporated boron films in the 6.8-900 eV photon energy range

Mónica Fernández-Perea, Juan I. Larruquert, José A. Aznárez, José A. Méndez, Manuela Vidal-Dasilva, Eric Gullikson, Andy Aquila, Regina Soufli, and J. L. G. Fierro

Abstract

The optical constants of electron-beam evaporated boron from 6.8 to 900eV were calculated through transmittance measurements of boron thin films deposited onto carbon-coated microgrids or LiF substrates in ultrahigh-vacuum conditions. In the low-energy part of the spectrum the measurements were performed in situ on freshly deposited samples, whereas in the high-energy range the samples were exposed to the atmosphere before the measurements. The extinction coefficient was calculated directly from the transmittance data, and a Kramers–Kronig analysis that combined the current data with data from the literature was performed to determine the dispersive part of the index of refraction. Finally, two different sum-rule tests were performed that indicated the good consistency of the data.