Wu Yiming, Dai Yanmeng, Jiang Shenlong, Ma Chao, Lin Yue, Du Dongxue, Wu Yukun, Ding Huaiyi, Zhang Qun, Pan Nan, Wang Xiaoping
Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
Phys Chem Chem Phys. 2017 Apr 5;19(14):9537-9544. doi: 10.1039/c7cp00973a.
Aluminium (Al)-doped zinc oxide (ZnO) nanowires (NWs) with a unique core-shell structure and a Δ-doping profile at the interface were successfully grown using a combination of chemical vapor deposition re-growth and few-layer AlO atomic layer deposition. Unlike the conventional heavy doping which degrades the near-band-edge (NBE) luminescence and increases the electron-phonon coupling (EPC), it was found that there was an over 20-fold enhanced NBE emission and a notably-weakened EPC in this type of interfacially Al-doped ZnO NWs. Further experiments revealed a greatly suppressed nonradiative decay process and a much enhanced radiative recombination rate. By comparing the finite-difference time-domain simulation with the experimental results from intentionally designed different NWs, this enhanced radiative decay rate was attributed to the Purcell effect induced by the confined and intensified optical field within the interfacial layer. The ability to manipulate the confinement, transport and relaxation dynamics of ZnO excitons can be naturally guaranteed with this unique interfacial Δ-doping strategy, which is certainly desirable for the applications using ZnO-based nano-photonic and nano-optoelectronic devices.
通过化学气相沉积再生长和少层氧化铝原子层沉积相结合的方法，成功生长出具有独特核壳结构且界面处具有δ掺杂分布的铝（Al）掺杂氧化锌（ZnO）纳米线（NWs）。与传统重掺杂会降低近带边（NBE）发光并增加电子-声子耦合（EPC）不同地是，发现在这种界面Al掺杂的ZnO纳米线中，NBE发射增强了20倍以上，且EPC显著减弱。进一步的实验揭示了非辐射衰减过程得到极大抑制，辐射复合率大幅提高。通过将有限时域差分模拟与故意设计的不同纳米线的实验结果进行比较，这种增强的辐射衰减率归因于界面层内受限和增强的光场引起的珀塞尔效应。这种独特的界面δ掺杂策略自然能够保证对ZnO激子的限制、传输和弛豫动力学进行调控，这对于基于ZnO的纳米光子和纳米光电器件的应用来说无疑是非常理想的。
