Author
Abstract
Structural and optical property was studied as a function of film thickness for
thermally evaporated CdI2 films. Stoichiometric films (up to 250 nm thickness) showing
hexagonal structure, and good c-axis alignment normal to glass substrate plane. The
optical absorption data indicate an allowed direct inter – band transition near the
absorption edge with optical energy gap varies continuously from 2.9 eV to 3.6 eV.Part
of the optical data was fitted to an indirect type transition to determine the indirect optical
energy gap which also varies continuously from 2.2 eV to 3.1 eV . Both energy gaps
show thickness dependences, which can be explained qualitatively by a thickness
dependence of the grain size through the decreasing of the grain boundary barrier height
with grain size.
Keywords
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