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
• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: FUNDAMENTAL AREAS OF PHENOMENOLOGY(INCLUDING APPLICATIONS)
• 页码范围: 54-59
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/0256-307X/38/7/074201

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.