الفهرس 
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Abstract
The thesis consists of two parts, the ”effect of the carrier gas on morphological, optical and electrical properties of SnO2 nanostructures prepared by vapor transport” and the ”morphologies and optical properties of mixed tin oxysulfide produced by evaporation condensation of SnS”.The synthesized nanomaterials are of technologically interest.The aim of the first part was to explore the effects of carrier gas
on the properties of SnO2 nanostructures grown by vapor transport
method for possible optoelectronic applications. Nanostructures of SnO2
were synthesized via vapor transport method using Ar plus O2 and N2
plus O2 gas mixtures. It was found that the carrier gas (Ar or N2) has great
influences on the properties of the resulting SnO2 nanostructures.
Tetragonal single phase SnO2 with nanowires (NWs) morphologies was
obtained for Ar/O2. The diameters of the NWs ranged from 10 to 162 nm
and the lengths exceed 5 µm. While tetragonal single phase SnO2 with
nanoparticles morphologies (diameters of 42 - 173 nm nm) was obtained
for N2/O2. The calculated optical band gap values were 3.81 eV and 2.95
eV for samples prepared with Ar/O2 and N2/O2, respectively. The
conduction mechanism in the samples was found to be thermally
activated. Single activation energy of 0.49 eV was evaluated for the
sample prepared in Ar/O2, while two activation energies (EAL = 1.48 eV
and EAh = 0.83 eV) were obtained for the sample prepared with N2/O