氨气退火对ZnO纳米线阵列光致发光性质的影响

The Effect of NH_3 Anneal on the Photoluminescence Properties of ZnO Nanowires Array

采用水热方法在Si(100)衬底上制备ZnO纳米线.利用提拉法在Si衬底上首先制备ZnO晶种层,然后利用水热法在晶种层上生长ZnO纳米线.在不同温度下的NH3气氛中,对ZnO纳米线进行退火处理.系统地研究了NH3退火对ZnO纳米线光学性质的影响,在低温光致发光光谱中观察到了与氮受主相关的光发射,并通过自由电子-受主辐射复合光发射确定受主离化能为129meV.实验结果还表明,随着退火温度的升高,施主-受主对辐射复合发光呈现了微弱红移现象.在700℃退火的条件下制备的ZnO纳米线的低温PL谱中,观察到较为明显的自由激子光发射,并采用理论拟合进行证明.

The ZnO nanowires were prepared on Si （100） substrate by hydrothermal technology. Prior to the growth of nanowires, thin ZnO seed layer was prepared on the surface of Si substrate by coating. Then, oriented ZnO nanowires were grown on the seed layer through hydrothermal method. The ZnO nanowires were annealed in NH3 at different temperatures. The effect of anneal on their photoluminescence （PL） properties were systematically studied. N acceptor-related emissions appeared in low-temperature PL spectra. The ionization energy of N acceptor was determined as 129 meV from free-electron-to-acceptor （FA） transition. In addition, donor-acceptor pair （DAP） emission showed a slight redshift with increasing annealing temperature. An obvious free-exiton （FE） emission was observed in the PL spectra of ZnO nanowires annealed at 700℃. This phenomenon was proved with theory fitting.