Use of Thin Films in Determining the Optical Constants of PbS from 1 to 5 eV

Abstract

Reflectance and transmittance measurements have been made on four epitaxial thin films of PbS ranging in thickness from 260 to 830 Å, in the spectral region from 1 to 5 eV. The optical constants of each film have been derived in order to demonstrate the usefulness of the data obtained from such thin samples. The results are self-consistent and are in good agreement with the bulk optical constants obtained by Avery. The uncertainty in the magnitude of the optical constants derived from thin-film data is approximately equal to the uncertainty in the data themselves if the film thickness is accurately known. The thin-film approach to the derivation of optical constants is shown to be superior to the use of dispersion relations in many cases. The problems and advantages encountered in the use of thin-film samples are discussed.