Observation of Photoconductivity in Sn-Doped ZnO Nanowires and Their Photoenhanced Field Emission Behavior

Abstract

Sn-doped ZnO nanowire films have been successfully synthesized by electrodeposition on zinc foil followed by annealing in air at 400°C for 4 h. The XRD patterns of the annealed specimens exhibit a set of welldefined diffraction peaks indexed to the wurtzite phase of ZnO. The surface morphology of the as-synthesized films showed a network of densely packed flakes/sheets on the substrate. However, upon annealing, the formation of ZnO nanowires, processing length in the range of several micrometers and diameter less than 150 nm, on the entire substrate is observed. The relative atomic percentage of Sn, estimated from the energy dispersive spectra, was found to be 0.5 and 2.0 in the ZnO films deposited for 10 and 40 min durations, respectively. From the field emission studies, the values of the turn-on field and threshold field, required to draw emission current density of 10 and 100 µA/cm 2 , are observed to be 0.68 and 1.1 V/µm for 0.5% Sndoped ZnO and 1.72 and 2.25 V/µm for 2.0% Sn-doped ZnO, respectively. The field emission current stability investigated for a duration of 6 h at the preset value of 100 µA is found to be excellent. A prominent photoenhancement in the field emission current upon visible light illumination of the Sn-doped ZnO nanowires films has been observed. This enhancement has been attributed to the photoconductivity of the Sn-doped ZnO.

Comparative investigation on cation-cation (Al-Sn) and cation-anion (Al-F) co-doping in RF sputtered ZnO thin films: Mechanistic insight

“…The inset in Fig. 6(A) shows signals at around 486.83 eV and 495.2 eV corresponding to Sn 3d 5/2 and Sn 3d 3/2 peaks which confirms the presence of only Sn 4+ in ATZO similar to other reports [57][58]. However, if Sn 4+ substitutes Zn 2+ , an enhanced carrier concentration would have been obtained.…”

Controllable Ag nanoparticle coated ZnO nanorod arrays on an alloy substrate with enhanced field emission performance

“…Especially, ZNAs or ZNWs has attracted more attentions due to advantages of controllable morphology, environment-friendship, low cost, and feasibility of large scale growth. 9,10 In the past few years, great efforts have been made to improve the FE performances of ZNAs or ZNWs, such as doping, [11][12][13] coating with other materials, [14][15][16] or growing on the conducting substrate. 17,18 Among these methods, one of the most effective strategies is to construct ZnO based composite FE materials, which can either enhance the emission sites by forming a rough surface, or improve its conductivity due to the synergistic effect between different materials.…”

Effect of Sn doping on structural, optical, electrical and wettability properties of oriented ZnO nanorod arrays

“…This is most desirable method for preparation of ZnO arrays owing to its simplicity, non-vacuum system of deposition, inexpensive and also seed layer free. The doping of Sn in ZnO arrays is expected to modify the optical, electrical and other physical or chemical properties of ZnO because of the different electronic shell structure [30][31][32]. Furthermore, Zn can be easily substituted by Sn due to their almost equal radii (r Zn þ2 ¼ 0:074 nm and r Sn 4þ ¼ 0:069 nm).…”