Song Changkun, Wang Peng, Qian Yinping, Zhou Guofu, Nötzel Richard
Opt Express. 2020 Aug 31;28(18):25750-25756. doi: 10.1364/OE.400590.
We demonstrate enhanced THz radiation from p-InAs (100) by advanced heterostructure design. The THz radiation from InAs (100) under ultra-short pulsed laser excitation is due to the photo-Dember effect. Inserting a thin n-InGaAs layer close to the InAs surface effectively blocks the hole diffusion while the electron diffusion is still efficient due to tunneling. Therefore, enhanced photogenerated electron-hole separation and photo-Dember electric field is achieved to enhance the THz emission. The layer structure and doping profile are confirmed by secondary ion mass spectrometry and X-ray diffraction. The blocking of the hole diffusion is independently verified by the surface photovoltage measured by Kelvin probe force microscopy.
我们通过先进的异质结构设计展示了p-InAs(100)增强的太赫兹辐射。在超短脉冲激光激发下，InAs(100)产生的太赫兹辐射归因于光丹伯效应。在InAs表面附近插入一层薄的n-InGaAs层，能有效阻止空穴扩散，而由于隧穿效应电子扩散仍然有效。因此，实现了增强的光生电子-空穴分离和光丹伯电场，从而增强了太赫兹发射。通过二次离子质谱和X射线衍射确定了层结构和掺杂分布。通过开尔文探针力显微镜测量的表面光电压独立验证了空穴扩散的阻挡。
