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研究了KrF准分子激光辐照对ZnO薄膜的本征缺陷.紫外(UV)发光以及表面形貌的影响,并对室温下ZnO的UV发射机理进行了详细探讨.结果表明激光辐照打断了薄膜内Zn—O键,氧空位(锌填隙)增多,导致表面电阻率下降,载流子浓度升高,调节激光辐照能量密度,可在较大范围内调控ZnO薄膜中的施主缺陷浓度;同时在激光热效应作用下,薄膜晶粒熔融长大,表面粗糙度大大降低;室温下ZnO薄膜的UV发光包括自由激子复合发光(FX)及其声子伴线(FX-LO),缺陷浓度决定了FX与FX-LO的相对强度比,进而影响UV发射峰的强度以及位置.因此,激光辐照可以快速、有效地对ZnO薄膜内的缺陷浓度进行调控,从而控制其室温下的UV发射强度,这对于提高ZnO基光电器件的性能具有重要意义.
The effects of KrF excimer laser irradiation on the intrinsic defects of ZnO thin films, UV luminescence and surface morphology were investigated. The mechanism of UV emission at room temperature was discussed in detail. The results showed that laser irradiation was interrupted The increase of Zn-O bond and oxygen vacancy (zinc interstitial space) in the film led to the decrease of surface resistivity and the increase of carrier concentration, and the energy density of laser irradiation could be adjusted to control the concentration of donor defect in the ZnO thin film At the same time, under the action of laser thermal effect, the crystal grains of the thin films melt and grow greatly, and the surface roughness is greatly reduced. The UV luminescence of ZnO films at room temperature includes free exciton complex luminescence (FX) and its phonon companion (FX-LO) The concentration determines the relative intensity ratio of FX to FX-LO, which in turn affects the intensity and location of the UV emission peak. Therefore, laser irradiation can quickly and effectively control the defect concentration in the ZnO thin film to control its UV Emission intensity, which is of great significance for improving the performance of ZnO-based optoelectronic devices.