Zn基柱状ZnO取向生长机制

通过预氧化处理在Zn基底上制备了ZnO颗粒膜, 并由N₂H₄·H₂O-水热体系制备了Zn基柱状ZnO阵列。实验发现, 在Zn单一晶体学取向表面上柱状ZnO高度有序排列, 据此提出了Zn基柱状ZnO的自由生长取向机制。水热反应条件下, ZnO微晶通常具有沿c轴优先生长的结晶习性, 柱状体高度有序排列取决于ZnO晶核的状态。单一晶体学取向表面上晶核的状态一致, 决定了ZnO柱状体取向一致。Zn基柱状ZnO阵列光致发光谱分析表明, 在30~60 K之间, 近带边激子发射峰强度呈现反常温度依赖的“负热淬灭”现象, 该过程包含了两个无辐射过程和一个负热淬灭过程。

Alignment Growth Mechanisms of Rod-like ZnO on Zinc Substrates

Discontinuous films of ZnO particles were prepared on zinc substrates by air pre-oxidation process. The arrays of rod-like ZnO nano-/micro- crystals on zinc substrates were synthesized through hydrothermal processing with N₂H₄·H₂O solution. It is found that the rod-like ZnO nano-/micro-crystals align well on the substrate surface with a unique crystallographic orientation. The experimental results suggest a free alignment growth mechanism for rod-like ZnO nano-/micro-crystals on zinc substrates. The crystallization habit of ZnO nano-/micro-crystals is to grow along with the c axis fast under hydrothermal conditions, thus the well alignment of rod-like ZnO nano-/micro-crystals only depends on the state of ZnO nuclei on the substrate surface. The states of ZnO nuclei on the substrate surface with a unique crystallographic orientation well agree with others, which regulates the alignment of rod-like ZnO nano-/micro-crystals. In temperature-dependent photoluminescence spectra, the "negative thermal quenching" phenomenon of near band-gap edge excitons is observed in the temperature ranging from 30 K to 60 K, which identify two non-radiative processes and one negative thermal quenching process.