电沉积ZnO纳米柱的光学带隙与非辐射复合EI北大核心CSCD

为实现ZnO纳米柱阵列材料在新型纳米结构化太阳能电池中的应用,需要对纳米柱的几何形貌与光电特性进行调控。ZnO纳米柱阵列材料的制备方法为电化学沉积方法。通过在生长溶液中使用In(NO_(3))_(3)和NH_(4)NO_(3),实现了对纳米柱的直径、阵列密度、柱间距、光学带隙、近带边发射、斯托克斯位移等物理性质的调控。采用扫描电子显微镜、X射线衍射仪、分光光度计、光致发光测试仪对样品的形貌、晶体性质、透射反射性质、光致发光性质进行测试与表征。结果表明,使用NH_(4)NO_(3)将紧密排列的ZnO纳米柱阵列密度降低了51%,导致柱间距增大至超过100 nm,同时可将纳米柱的直径降低至22 nm。使用In(NO_(3))_(3)使ZnO纳米柱的光学带隙展宽100 meV。通过NH_(4)NO_(3)的使用可在3.41 eV至3.55 eV范围内调控带隙。由于NH_(4)NO_(3)的引入,ZnO纳米柱的斯托克斯位移可降低至19 meV,表明NH_(4)NO_(3)的引入能够有效地抑制纳米柱阵列中的非辐射复合。

Optical gap energy of eletrodeposited ZnO nanorods and its non-radiative recombination

In order to achieve the applications of the ZnO nanorod arrays in the novel nanostructured solar cells, it is necessary to tailor and control the nanorods' morphological, optical and electrical properties. The ZnO nanorods arrays were fabricated by electrodeposition. The physical properties such as the diameter, density, distance, optical band gap energy, near band emission and Stokes shift can be adjusted by the use of In(NO₃)₃ and NH₄NO₃.The characterizations such as scanning electron microscopy, X-ray diffraction spectrometer and photoluminescence were used to measure the samples' morphology, crystal property, transmission and reflection and photoluminescence properties. According to the measurement results, the ZnO nanorod arrays' density is reduced to 5.9×10⁹ cm^-2 and the distance between nanorods is enlarged to 108 nm by using NH₄NO₃. The nanorods' diameter is decreased to 22 nm. The use of In(NO₃)₃ leads to the blue shift of the ZnO nanorods' optical band gap energy by 100 meV. The optical band gap energy is further tailored between 3.41 eV and 3.55 eV by using NH₄NO₃. The ZnO nanorods' Stokes shift can be decreased to 19 meV by using NH₄NO₃, resulting in the effective suppression of the non-radiative recombination.