Transmittance of Thin Metallic Films in the Vacuum-Ultraviolet Region Below 1000 Å

Abstract

The transmittance of titanium, tellurium, antimony, beryllium, aluminum, gold, and silver films has been measured in the vacuum-ultraviolet region below 1000 A, using a 1-m Seya monochromator together with a line-emission capillary spark source. In Ti, transmittance started at 18 eV, as observed earlier, rose to a peak value at 31.5 eV, then decreased to less than 0.1% near 38 eV, characterizing the M2, 3 absorption edge. The transmittance in Te has been measured from near its threshold at about 15 eV to a maximum at 38 eV, followed by a sharp drop between 39 and 40 eV and a subsequent rise towards shorter wavelengths. Antimony exhibited an onset of transmittance near 15 eV, increased to a maximum near 31 eV, from where it rapidly decreased to zero at 33 eV. At 37 eV it rose again to a second maximum at 39.5 eV and went to zero at 42 eV. In Be, transmittance began near 19 eV, which is compared to nearby values of both the plasma frequency and characteristic electron energy losses. Some new transmittance curves for Al, extended towards shorter wavelengths than reported in earlier work, are also presented here, primarily because Al films were used as a backing layer for the measurements on Te, Sb, and Be films. No transmittance was observed in Ag and Au films down to 250 A.