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利用光抽运-太赫兹探测技术,研究了ZnSe的载流子弛豫过程和太赫兹波段电导率的时间演化过程.在中心波长为400 nm的抽运光作用下,ZnSe的载流子弛豫过程用双指数函数进行了很好的拟合,其快的载流子弛豫时间和慢的载流子弛豫时间均随抽运光密度的增加而增大.快的载流子弛豫时间随抽运光密度的增加而增大与样品中的缺陷有关,随着激发光密度的增加,激发的光生载流子浓度增大,缺陷逐渐被光生载流子填满,致使快的载流子弛豫时间增大;慢的载流子弛豫时间随着抽运光密度增加而增大主要和带填充有关.不同抽运光延迟时间下ZnSe在太赫兹波段的瞬态电导率用Drude-Smith模型进行了很好的拟合.对ZnSe光致载流子动力学特性的研究为高速光电器件的设计和制造提供了重要的实验依据.
The optical pumping - terahertz detection technique was used to study the time evolution of ZnSe carrier relaxation and the terahertz wave band conductivity. At the center wavelength of 400 nm, the carrier relaxation of ZnSe The relaxation process is well-fitted by a double exponential function with fast carrier relaxation times and slow carrier relaxation times increasing with increasing pump optical density. Fast carrier relaxation Yu time increases with the increase of pumping optical density, which is related to the defects in the sample. With the increase of excitation optical density, the concentration of excited photo-generated carriers increases and the defect is gradually filled with photo-generated carriers, resulting in fast The carrier relaxation time increases and the slow carrier relaxation time increases with the increase of the pump optical density, which is mainly related to the band filling. The transient conductivity of ZnSe in the terahertz band with different pumping light delay time The Drude-Smith model is a good fit, and the research on the kinetic properties of ZnSe photocells provides an important experimental basis for the design and manufacture of high-speed optoelectronic devices.