Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, People's Republic of China.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Aug;76(3-4):336-40. doi: 10.1016/j.saa.2010.03.015. Epub 2010 Mar 20.
We studied the room temperature UV emission of ZnO films with different defect densities which is fabricated by KrF laser irradiation process. It is shown room temperature UV photoluminescence of ZnO film is composed of contribution from free-exciton (FX) recombination and its longitudinal-optical phonon replica (FX-LO) (1LO, 2LO). With increase of the defect density, the FX emission decreased and FX-LO emission increased dramatically; and the relative strengths of FX to FX-LO emission intensities determine the peak position and intensity of UV emission. What is more, laser irradiation with moderate energy density could induce the crystalline ZnO film with very flat and smooth surface. This investigation indicates that KrF laser irradiation could effectively modulate the exciton emission and surface morphology, which is important for the application of high performance of UV emitting optoelectronic devices.
我们研究了不同缺陷密度的 ZnO 薄膜在室温下的紫外发射，这些薄膜是通过 KrF 激光辐照工艺制备的。结果表明，ZnO 薄膜的室温紫外光致发光由自由激子（FX）复合及其纵光学声子模（FX-LO）（1LO、2LO）贡献组成。随着缺陷密度的增加，FX 发射减少，FX-LO 发射显著增加；并且 FX 与 FX-LO 发射强度的相对强度决定了紫外发射的峰位置和强度。更重要的是，具有适中能量密度的激光辐照可以诱导具有非常平坦和光滑表面的结晶 ZnO 薄膜。这项研究表明，KrF 激光辐照可以有效地调节激子发射和表面形貌，这对于高性能紫外发光光电器件的应用非常重要。
