Quenching of the transient miniband photoconductivity in semiconductorsuperlattices due to a cancellation of field acceleration by Bragg reflection
Quenching of the transient miniband photoconductivity in semiconductorsuperlattices due to a cancellation of field acceleration by Bragg reflection
复制标题
由于布拉格反射消除场加速而导致半导体超晶格中瞬态微带光电导的淬灭
DOI：
10.1103/physrevb.86.161305
复制
发表时间：
2012
影响因子：
3.7
通讯作者：
K. Hirakawa
中科院分区：
文献类型：
--
作者：
T. Ihara;J. R. Cardenas;Y.Sakasegawa;R. Ferreira;G. Bastard;K. Hirakawa
本文利用时域太赫兹（THz）光谱研究了半导体超晶格（SL）微带中光激发电子的瞬态电导率。当飞秒激光脉冲的泵浦光子能量处于SL小波段能量范围内时，观察到明显的布洛赫发射。然而，当泵浦光子能量远高于微带时，布洛赫发射消失，取而代之的是由于光学整流效应而出现的太赫兹发射。这一事实可以解释为，当微带被超微带飞秒激光脉冲光激发的电子均匀地填充在空间中时，由于Bragg反射抵消了场加速度，导致瞬态微带输运的猝灭。
We have investigated transient conductivity of photoexcited electrons in the miniband of a semiconductor superlattice (SL) by using time-domain terahertz (THz) spectroscopy. When the pump photon energy of the femtosecond laser pulses lies in the SL miniband energy range, clear Bloch emission is observed. However, when the pump photon energy is set much above the miniband, the Bloch emission disappears and, instead, THz emission due to the optical rectification effect shows up. This fact can be interpreted as the quenching of transient miniband transport due to the cancellation of field acceleration by the Bragg reflection when the miniband is uniformly populated inspace by electrons photoexcited by the above-miniband femtosecond laser pulses.