Department of Physics, Chemistry, and Biology-IFM, Linköping University, SE-583 81 Linköping, Sweden.
Nanotechnology. 2013 May 31;24(21):215202. doi: 10.1088/0957-4484/24/21/215202. Epub 2013 Apr 26.
We report the fabrication of quantum wells in ZnO nanowires (NWs) by a crystal phase engineering approach. Basal plane stacking faults (BSFs) in the wurtzite structure can be considered as a minimal segment of zinc blende. Due to the existing band offsets at the wurtzite (WZ)/zinc blende (ZB) material interface, incorporation of a high density of BSFs into ZnO NWs results in type II band alignment. Thus, the BSF structure acts as a quantum well for electrons and a potential barrier for holes in the valence band. We have studied the photoluminescence properties of ZnO NWs containing high concentrations of BSFs in comparison to high-quality ZnO NWs of pure wurtzite structure. It is revealed that BSFs form quantum wells in WZ ZnO nanowires, providing an additional luminescence peak at 3.329 eV at 4 K. The luminescence mechanism is explained as an indirect exciton transition due to the recombination of electrons in the QW conduction band with holes localized near the BSF. The binding energy of electrons is found to be around 100 meV, while the excitons are localized with the binding energy of holes of ∼5 meV, due to the coupling of BSFs, which form QW-like structures.
我们通过晶体相工程方法在 ZnO 纳米线（NWs）中制造量子阱。纤锌矿结构中的基面堆垛层错（BSF）可以被认为是闪锌矿的最小片段。由于在纤锌矿（WZ）/闪锌矿（ZB）材料界面处存在带隙偏移，将高密度的 BSF 掺入 ZnO NWs 中会导致 II 型能带排列。因此，BSF 结构充当电子的量子阱和价带中的空穴的势垒。我们研究了含有高浓度 BSF 的 ZnO NWs 的光致发光性质，与具有纯纤锌矿结构的高质量 ZnO NWs 进行了比较。结果表明，BSF 在 WZ ZnO 纳米线中形成量子阱，在 4 K 时在 3.329 eV 处提供附加的发光峰。发光机制解释为由于在 QW 导带中的电子与局部化在 BSF 附近的空穴的复合导致的间接激子跃迁。发现电子的结合能约为 100 meV，而激子被束缚在 BSF 形成的 QW 样结构的约 5 meV 的空穴结合能处。
