纳米硅结构中分裂能级对光电输运特性的影响

基于电子在分裂能级系统中同时存在的共振隧穿和子带输运过程,结合光生载流子作用提出了纳米硅结构中的光电输运理论模型.利用该模型计算了纳米硅结构在光照条件下的电流密度、电场强度及电子浓度分布.结果表明,光生电子在具有分裂能级的纳米硅中是以共振隧穿为主要输运方式.在此基础上,详细研究了光电流与吸收系数、外加偏压以及纳米硅层层数之间的关系,发现在特定的外界条件下光电流会出现跳变增加的现象,其物理原因是纳米硅结构中电场强度的二次分布.

Eeffects of split-level energy on optoelectronic transport in nanocrystalline silicon

Considering the coexisting of electron resonant tunneling and miniband transport processes in a split-level energy system, and the effect of photogenerated carrier, we propose an optoelectronic transport theoretical model for the nanosilicon structure. We employ this model to calculate current density, electric field and electron density distribution under illumination, and the results show that resonant tunneling plays a major role in transporting the photogenerated electrons in a nanosilicon structure. Furthermore, we study the relationship between the photocurrent and the absorption coefficients, the applied bias, and the number of nanolayers. It is found that under certain conditions, hopping phenomenon occurs with photocurrent increasing, which is due to the redistribution of electric field inside the nanosilicon structure.