Thin films of tin oxide were prepared by room temperature thermal evaporation of blue-black SnO crystal powder synthesized from metallic tin on glass substrate. X-ray diffractograms revealed that the amorphous samples form polycrystals of SnO when annealed at 300 degree(s)C in ambient air for 30 minutes and are oxidized to polycrystals of SnO2 when further annealed at 500 degree(s)C or above. The 2(theta) of the x-ray diffractogram peaks were produced by (101), (110), (211), (200), (112) planes of SnO and (110), (101), (211), (200), (220) planes of SnO2, respectively, as assigned by the ASTM index. Even though the optical energy gap of SnO (2.4 - 2.6 eV), is smaller compare to that of SnO2 (3.0 - 3.2 eV), the average strength of optical transition is highest for SnO polycrystals with a magnitude of 14.0 eV as compared to 10.4 eV for SnO2. The single oscillator strengths are 4.0 and 3.5 eV for polycrystalline SnO and SnO2 respectively. The plasma frequency was determined to be in the range of (6.1 - 11.8) X 1015 Hz and increases with increasing composition of SnO2; this parameter was used to estimate the density of valence electron in this material.
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