利用时域太赫兹波谱法的超高电场下砷化镓内能带耦合现象研究  

Strong Band Mixing in Bulk GaAs under High Electric Field Investigated by Time-Domain Terahertz Spectroscopy

作　　者：朱亦鸣[1,2] 张大伟[1] 何波涌[2] 庄松林[1] 

机构地区：[1]上海理工大学光学与电子信息工程学院,上海200093 [2]上海交通大学微电子学院,上海200240

出　　处：《中国激光》2009年第2期328-332,共5页Chinese Journal of Lasers

摘　　要：利用时域太赫兹波谱系统,研究了超高电场下砷化镓中的非平衡载流子的动态运动过程。研究发现,当电场小于50 kV/cm时,电子运动所辐射出的太赫兹波信号的最初峰值△E_(THz)(对应电子在Γ谷中的加速)随着电场的增加不断增大;当电场大于50 kV/cm时,△E_(THz)随着电场的增大逐渐衰减并最终达到饱和。这一实验结果表明,当电场强度大于50 kV/cm时,由砷化镓中的电子的有效加速质量随着电场的增加而显著地增加(在300kV/cm的情况下电子的有效加速质量约为低电场时的30倍)。导致这一结果的原因是在超高电场的情况下砷化镓中的能带会发生强烈的混合。Nonequilibrium transport of carriers in bulk GaAs under very high electric fields is investigated by timedomain terahertz （THz） emission spectroscopy. It is found that the initial peak height of THz emission waveforms （△ETHz ） , which are corresponding to the acceleration of electrons in the Γ valley, gradually increases with increasing bias electric fields F0, for F0〈50 kV/cm and saturates at - 1 THz above 50 kV/cm. The experimental results show that the effective acceleration mass of electrons under high electric fields significantly increases with increasing fields （30 times at 300 kV/cm than low bias electric fields）, most likely due to strong band mixing under very high fields.

关 键 词：测量 电子飞秒加速 非平衡载流子 时域太赫兹波谱法 

分 类 号：O473[理学—半导体物理]