Synthesis of ZnO Nanowires Having pn Junction by NAPLD and Their Applications

本课题取得的主要成果如下：(1)利用NAPLD成功地合成了磷掺杂的氧化锌纳米线。通过低温光致发光和荧光寿命测量发现，P或Sb的掺杂形成了受主能级，延长了其寿命。还观察到与n型电导有关的绿色荧光因掺杂而减弱。(2)P离子注入也实现了P掺杂。高能磷离子注入的氧化锌纳米线颜色变黄，表明晶体结构被破坏。结果表明，脉冲激光退火法对氧化锌晶体的损伤修复是非常有效的。离子注入和激光退火法是实现纳米线p-n结的一种很有前途的方法。(3)提出了一种将Sb薄层作为催化剂和掺杂剂的新方法。利用该方法成功地合成了Sb掺杂的氧化锌纳米线和纳米片。(4)将NAPLD和常规PLD相结合，成功地合成了核壳结构的氧化锌纳米线。该方法有利于实现沿纳米线径向的p-n结。(5)通过适当调整NAPLD中的生长条件，可以制备出具有纳米结构的氧化锌。纳米氧化锌显示出优异的场发射性能。

The results obtained by this project are summarized as follows.(1)P-doped ZnO nanowires were successfully synthesized by NAPLD. It was observed by low temperature photoluminescence and the fluorescence lifetime measurement that the acceptor levels were formed and the lifetime was elongated by doping P or Sb. It was also observed that the green fluorescence that is considered to be related to the n-type conduction was weakened by the doping.(2) P-doping was also realized by the P ion-injection. The color of the ZnO nanowires injected by high energy P ions turned to be yellowsh, indicating that the crystal structure was damaged. It was found that the pulsed-laser annealing is quite effective to recover the damaged ZnO crystals. The ion injection followed by the laser annealing will be one of the promising method for the realization of p-n junction within a nanowires.(3) A new method where the thin Sb layer is used as both catalyst and the dopant has been proposed. Sb-doped ZnO nanowires and nanosheets were successfully synthesized by this method.(4) A core-shell structured ZnO nanowires have been successfully synthesized by combining NAPLD and conventional PLD. This method is useful to realize p-n junction along the radial direction of the nanowires.(5) It was found that the nanowall-structure of ZnO can be synthesized by properly adjusting the growth condition in NAPLD. The nanowalled ZnO showed an excellent field emission property.