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FIZIKA A 5 (1996) 3, 153-162
 
STUDIES ON CHEMICALLY DEPOSITED FILMS OF BISMUTH-SULFIDE (Bi2S3)
SIHAM MAHMOUD
Physics Department, N.R.C., Cairo, Egypt
Received 28 March 1996
Revised manuscript received 19 August 1996
The chemical method for deposition of bismuth-sulfide (Bi2S3)
thin films is presented. For the deposition, the triethanolamine complex of bismuth
nitrate was allowed to react with aqueous thiourea solution. Good quality (very uniform,
reproducible, tightly adherent, specularly reflecting and crack free) deposits are
obtained. Micro-structural characterizations were carried out by X-ray diffraction (XRD)
and scanning electron microscope (SEM) in order to study the crystallinity and the surface
topography of the films. The studies establish that bismuth-sulfide thin films become weak
crystalline phase upon annealing in air near 393 K and remain stable up to 573 K. The SEM
photographs reveal that crystal size and perfection increase when increasing the thickness
of the film. The thermal stability of the powder samples was studied also, using a
Shimadzu DSC-50 scanning calorimeter. From the electrical measurements, an activation
energy of 0.155 eV was obtained in the temperature range of 300 K to 363 K. The conduction
above 363 K was found to be intrinsic with a band-gap of 1.38 eV.
UDC 538.975
PACS 68.60.-p
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