Seki Kazuhiko, Wojcik Mariusz, Tachiya M
National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 5, Tsukuba, Ibaraki 305-8565, Japan.
J Chem Phys. 2006 Jan 28;124(4):044702. doi: 10.1063/1.2161213.
The photoluminescence in amorphous semiconductors decays according to the power law t(-delta) at long times. The photoluminescence is controlled by dispersive transport of electrons. The latter is usually characterized by the power alpha of the transient current observed in the time-of-flight experiments. Geminate recombination occurs by radiative tunneling which has a distance dependence. In this paper, we formulate ways to calculate reaction rates and survival probabilities in the case carriers execute dispersive diffusion with long-range reactivity. The method is applied to obtain tunneling recombination rates under dispersive diffusion. The theoretical condition of observing the relation delta=alpha/2+1 is obtained and theoretical recombination rates are compared to the kinetics of observed photoluminescence decay in the whole time range measured.
非晶半导体中的光致发光在长时间下按照幂律t^(-δ)衰减。光致发光由电子的色散输运控制。后者通常由飞行时间实验中观察到的瞬态电流的幂指数α来表征。双生复合通过具有距离依赖性的辐射隧穿发生。在本文中，我们阐述了在载流子进行具有长程反应性的色散扩散情况下计算反应速率和存活概率的方法。该方法用于获得色散扩散下的隧穿复合速率。得到了观察δ = α/2 + 1关系的理论条件，并将理论复合速率与在整个测量时间范围内观察到的光致发光衰减动力学进行了比较。
