Electrical and optical properties of single-crystalline SnO\(_2\) nanowires: experiment and theory

The single-crystalline of tin oxide (SnO\(_2\)) nanowires (NWs) have been synthesized successfully via chemical vapour deposition and structurally characterized by using x-ray powder diffraction, transmission electron microscopy and high-resolution transmission electron microscopy. The optical absorption of the SnO\(_2\) NWs were measured by spectrophotometer. Here, we also have performed first principles calculations based on density functional theory to investigate the band structure and dielectric function of this SnO\(_2\) NWs to expose the luminescence mechanism. It is observed that the bandgap energy of the SnO\(_2\) NWs to be 3.68 eV, exhibiting a 80 meV blue shift from that of the bulk SnO\(_2\). In a subsequent ab initio electronic structure calculation, the effects of defects (e.g., O and Sn vacancies) on the nature and origin of absorption are investigated for the single-crystalline system. Electronic structure calculations suggest electronic doping to be more effective to stabilize the absorption and the dielectric function results are consistent with the experimental phenomenon.