Investigation of Nanoscale Voids in Sb-Doped p-Type ZnO Nanowires

摘要

While it has multiple advantageous optoelectronic and piezoelectric properties, application of zinc oxide has been limited by the lack of a stable p-type dopant. Recently, it was discovered that antimony doping can lead to stable p-type doping in ZnO, but one curious side effect of the doping process is the formation of voids inside the nanowire. While previously used as a signifier of successful doping, up until now, little research has been performed on these unusual structures themselves. In this work, the effect of annealing on the size and microstructure of the voids was investigated using TEM and XRD, finding that the voids form around a region of Zn_7Sb_2O_(12), as opposed to a simple planar precipitate of Sb atoms as once theorized. Furthermore, using Raman spectroscopy, a new peak associated with successful doping was identified, allowing for a high throughput means of detecting successful Sb doping. The most surprising finding, however, was the presence of water trapped inside the nanowire, showing that this is actually a composite structure. Water was initially discovered in the nanowires using atom probe tomography, and verified using Raman spectroscopy. Atom probe tomography was also used to verify that Sb clusters around the voids, agreeing with our previous observations. If water can be trapped in these nanowires, a limitless number of other water-soluble materials such as quantum dots and organic molecules, opening the possibility for further functionalization of this material.