Al-Saadi Mubarak J, Al-Harthi Salim H, Kyaw Htet H, Myint Myo T Z, Bora Tanujjal, Laxman Karthik, Al-Hinai Ashraf, Dutta Joydeep
Department of Physics, Sultan Qaboos University, PO Box 36, Al Khoudh, 123, Muscat, Oman.
Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, PO Box 17, Al Khoudh, 123, Muscat, Oman.
Nanoscale Res Lett. 2017 Dec;12(1):22. doi: 10.1186/s11671-016-1800-3. Epub 2017 Jan 6.
We report on the surface, sub-surface (top few nanometers) and bulk properties of hydrothermally grown zinc oxide (ZnO) nanorods (NRs) prior to and after hydrogen treatment. Upon treating with atomic hydrogen (H*), upward and downward band bending is observed depending on the availability of molecular HO within the structure of the NRs. In the absence of HO, the H* treatment demonstrated a cleaning effect of the nanorods, leading to a 0.51 eV upward band bending. In addition, enhancement in the intensity of room temperature photoluminescence (PL) signals due to the creation of new surface defects could be observed. The defects enhanced the visible light activity of the ZnO NRs which were subsequently used to photocatalytically degrade aqueous phenol under simulated sunlight. On the contrary, in the presence of HO, H* treatment created an electronic accumulation layer inducing downward band bending of 0.45 eV (~1/7th of the bulk ZnO band gap) along with the weakening of the defect signals as observed from room temperature photoluminescence spectra. The results suggest a plausible way of tailoring the band bending and defects of the ZnO NRs through control of HO/H* species.
我们报告了水热生长的氧化锌（ZnO）纳米棒（NRs）在氢处理前后的表面、亚表面（顶部几纳米）和体相性质。在用原子氢（H*）处理时，根据NRs结构中分子HO的可用性，观察到向上和向下的能带弯曲。在没有HO的情况下，H处理显示出对纳米棒的清洁作用，导致能带向上弯曲0.51 eV。此外，可以观察到由于新表面缺陷的产生，室温光致发光（PL）信号强度增强。这些缺陷增强了ZnO NRs的可见光活性，随后用于在模拟阳光下光催化降解苯酚水溶液。相反，在有HO的情况下，H处理产生了一个电子积累层，导致能带向下弯曲0.45 eV（约为体相ZnO带隙的1/7），同时从室温光致发光光谱中观察到缺陷信号减弱。结果表明，通过控制HO/H*物种，可以合理地调整ZnO NRs的能带弯曲和缺陷。
