Polarity Reversal of Terahertz Electric Field from Heavily p-Doped Silicon Surfaces  

作　　者：Hai-Zhong Wu Quan Guo Yan-Yun Tu Zhi-Hui Lyu Xiao-Wei Wang Yong-Qiang Li Zhao-Yan Zhou Dong-Wen Zhang Zeng-Xiu Zhao Jian-Min Yuan 吴海忠;郭泉;涂艳云;吕治辉;王小伟;李永强;周兆妍;张栋文;赵增秀;袁建民(College of Liberal Arts and Sciences,National University of Defense Technology,Changsha 410073,China;Northwest Institute of Nuclear Technology,Xi'an 710024,China;Graduate School of China Academic of Engineering Physics,Beijing 100193,China)

机构地区：[1]College of Liberal Arts and Sciences,National University of Defense Technology,Changsha 410073,China [2]Northwest Institute of Nuclear Technology,Xi'an 710024,China [3]Graduate School of China Academic of Engineering Physics,Beijing 100193,China

出　　处：《Chinese Physics Letters》2021年第7期34-39,共6页中国物理快报（英文版）

基　　金：Supported by the National Key Research and Development Program of China(Grant No.2019YFA0307704);the NSAF Joint Fund(Grant No.U1830206);the Major Research Project of National Natural Science Foundation of China(Grant No.91850201);the National Natural Science Foundation of China(Grant Nos.11974426,11974425,11874425,11774428,and 12074431).

摘　　要：Above-band-gap optical excitation of electron-hole pairs screens the doping-induced surface electric field and generates terahertz(THz)pulses via free-carrier transport.THz emission from a heavily doped silicon surface is much weaker than that of lightly doped samples.A polarity reversal of the THz electric field is observed in heavily doped p-type silicon,indicating that the doping related and carrier induced surface electric fields oppose each other.By comparing the penetration depth of the excitation laser with the thickness of the depletion layer for the doped silicon,it is shown that competition between diffusion and drift current causes the polarity reversal.

关 键 词：EXCITATION DOPING polarity 

分 类 号：TN304.12[电子电信—物理电子学]