二氧化钛纳米管阵列载流子超快动力学研究

Study of Ultrafast Carrier Dynamics in Titanium Dioxide Nanotube Arrays

采用阳极氧化电化学方法制备了二氧化钛(Ti O2)纳米管阵列,利用飞秒激光泵浦-探测技术检测了Ti O2纳米管阵列的瞬态反射率变化,进而研究载流子超快动力学过程.实验结果表明:在经历最初的急剧下降后,反射率开始一个相对缓慢的回复过程.通过分析及数据拟合得到反射率快速回复的时间约为0.6ps.说明表面复合过程是影响样品载流子动力学的重要因素.在相对较慢的回复过程中,主要发生载流子向体内扩散以及体内复合的过程.并且载流子-声子,载流子-光子的散射过程对反射率变化也有一定影响作用.

TiO2 nanotube arrays was preparated by the method of electrochemical anodic oxidation.Fmtosecond laser pump-probe technique was used to detect the change of transient reflectance of the sample,and then the carrier ultrafast dynamics of Titanium dioxide（ TiO2） nanotube arrays was studied. The experiment results show that the reflectivity change appears a relatively slow recovery process after a rapid decline. The quick recovery time is 0. 6 ps through analyzing and fitting the data. It shows that the surface recombination process is one of the important factors that affect the sample carrier dynamics. In the process of the slow recovery： diffusion and recombination of carriers within the material body are the main processes.And the scattering between the carrier – phonons,carrier-photons also have certain effect on the reflectivity change.