Cu掺杂ZnO薄膜的结构及发光特性

Synthesis and Photoluminescence of Cu-doped ZnO Thin Films

采用溶胶-凝胶旋涂法在玻璃衬底上制备了不同Cu掺杂量的ZnO薄膜。用显微镜和X射线衍射(XRD)研究了Cu掺杂对ZnO薄膜形貌和微结构的影响。结果表明,制备得到的ZnO薄膜具有应变小和c轴择优取向。室温下测量了样品Zn1-xCuxO的光致发光(PL)谱,发现所有样品的PL谱中均观察到435nm左右的蓝光发光带,发光带强度与Cu的掺杂量有关;当x=0.06时,Zn1-xCuxO薄膜的PL谱中出现了较强的蓝光发射。分析了掺杂量对发光性能的影响,并对样品的发光机制进行了探讨,推断出蓝光峰来源于电子由导带底到锌空位(VZn)能级的跃迁及锌填隙(Zni)能级到价带顶的跃迁,它们可通过改变Cu的掺杂量予以控制。

Cu-doped ZnO thin films with different Cu concentration were fabricated on the glass substrate by means of sol-gel process. The surface morphology and microstructure were characterized by microscope and X-ray diffraction to investigate the influence of Cu doping. The XRD results reveal that all the ZnO thin film samples with small strain were well-oriented, and the grain size of Cu-doped ZnO film increases when the moderate Cu is introduced. Strong blue emission （-435nm） was observed for all samples at room temperature and the strongest emission is achieved as the Cu concentration is at 6%. The blue emission is assigned to the transition of electrons from the bottom of conduction band to zinc vacancy（VZn） or from zinc interstitial（Zni） to the top of valence band, which can be well controlled by Cu doping.