Effect of the carrier gas on morphological, optical and electrical properties of SnO2 nanostructures prepared by vapor transport

The aim of the study 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 O-2 and N-2 plus O-2 gas mixtures. It was found that the carrier gas (Ar or N-2) has great influences on the properties of the resulting SnO2 nanostructures. Tetragonal single phase SnO2 with nanowires (NWs) morphologies was obtained for Ar/O-2. The diameters of the NWs ranged from 10 to 162 nm and the lengths exceed 5 A mu m. While tetragonal single phase SnO2 with nanoparticles morphologies (diameters of 42-173 nm) was obtained for N-2/O-2. The calculated optical band gap values were 3.81 and 2.95 eV for samples prepared with Ar/O-2 and N-2/O-2, 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/O-2, while two activation energies (E-AL = 1.48 eV and E-Ah = 0.83 eV) were obtained for the sample prepared with N-2/O-2. The photoluminescence emission (intensity and shape) depended on the carrier gas. The observed emission peaks were assigned to the oxygen vacancies and the oxygen related defects. The obtained results may find applications in optoelectronics such as light emitting diodes.