Surface effects on photoluminescence of single ZnO nanowires

Application of Room Temperature Photoluminescence From ZnO Nanorods for Salmonella Detection

“…Deviation from stoichiometry results in defects associated with zinc or oxygen electric conductivity and DLE intensity increasing in oxygen deficient ZnO nanostructures decreasing NBE to DLE ratio [21][22][23] [21][22][23]. The NBE/DLE ratio of ZnO nanostructures increases with improvement of the stoichiometry [23].…”

“…The structural, optical and electrical properties of ZnO nanostructures are strongly interrelated [21][22][23]. Deviation from stoichiometry results in defects associated with zinc or oxygen electric conductivity and DLE intensity increasing in oxygen deficient ZnO nanostructures decreasing NBE to DLE ratio [21][22][23] [21][22][23].…”

“…However, the light emission properties of ZnO nanostructures are affected by surface layer depletion in case of a high surface to volume ratio [24]. The NBE and DLE intensities are reduced as photo-generated electrons are captured on surface increasing the band bending and excitons dissociate in the electrical field, induced by the surface charge [6,7,23]. Therefore, since PL properties of ZnO strongly depend on the electronic structure and the shape of surface band bending, the PL spectra of as grown ZnO nano-rods were recorded to compare with the spectra of ZnO layers immobilized by Anti-Salmonella antibodies and spectra obtained after adding Salmonella antigens of different concentrations.…”

Indirect optical transition due to surface band bending in ZnO nanotubes

“…Consequently, a built-in electric filed and the corresponding electrostatic potential will built up so that the energy bands bend upwards as they approach the surface and finally results in a surface depletion layer, which will strongly influence the PL properties of ZnO nanostructures. [40][41][42][43][44][45] Since ZnO nanostructures usually have a very large surface-volume ratio, the band bending due to near surface on the PL process become more significant. The smaller a nanostructure is, the larger surface-volume ratio and stronger band bending effect it will have.…”

Enhancement of the photoelectrochemical properties of Cl-doped ZnO nanowires by tuning their coaxial doping profile

“…It could be related with a higher surface density of the contributing states, their surface activation by the hole accumulation at the surface depletion, or the promotion of slower recombination processes related with the charge separation occurring in the built-in electric field layer. 8,14,[20][21][22][23][24][25][26] In ambient conditions, the ZnO NWs surface is covered by ionized oxygen species and hydroxyl groups that trap conduction electrons, causing an upward bending of the ZnO energy bands at the surface. While highly doped ZnO screens the surface charge within a very thin surface layer, much thicker depletion regions characterize undoped semiconductors.…”