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FIZIKA A 4 (1995) 1, 45-53
 
PHYSICAL PROPERTIES OF d-Bi2O3
THIN FILMS
HAMDIA A. ZAYED
University College for Girls, Ain Shams University, Cairo, Egypt
Received 3 September 1994
Revised manuscript received 7 December 1994
Polycrystalline thin films of d-Bi2O3
were prepared by oxidising bismuth films of thickness (120-350 nm) in air at 473 K for 10
hours. X-ray diffraction analysis showed that the films are polycrystalline and correspond
to cubic d-phase of Bi2O3. The electrical
and optical properties of d-Bi2O3
were studied. The effect of the film thickness on these properties was also investigated.
From the electrical conductivity measurements at various temperatures (100-473 K), the
coexistence of band and multiphonon-assisted hopping conduction between well-localized
states has been observed. It was found also that the activation energy DE
increases and the density of localized states at the Fermi level gr decreases
with increasing thickness of the film. The analysis of the absorption coefficient data
revealed the existence of an indirect transition. It was found that the calculated value
of the optical energy gap Egopt increases with increasing thickness
of the film.
UDC 538.975
PACS 73.61.-r
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