Migration-Enhanced Epitaxial Growth of InAs/GaAs Short-Period Superlattices for THz Generation

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Abstract
The low-temperature-grown InGaAs (LT-InGaAs) photoconductive antenna has received great attention for the development of highly compact and integrated cheap THz sources. However, the performance of the LT-InGaAs photoconductive antenna is limited by its low resistivity and mobility. The generated radiated power is much weaker compared to the low-temperature-grown GaAs-based photoconductive antennas. This is mainly caused by the low abundance of excess As in LT-InGaAs with the conventional growth mode, which inevitably gives rise to the formation of As precipitate and alloy scattering after annealing. In this paper, the migration-enhanced molecular beam epitaxy technique is developed to grow high-quality (InAs)m/(GaAs)n short-period superlattices with a sharp interface instead of InGaAs on InP substrate. The improved electron mobility and resistivity at room temperature (RT) are found to be 843 cm2/(V·s) and 1648 ohm/sq, respectively, for the (InAs)m/(GaAs)n short-period superlattice. The band-edge photo-excited carrier lifetime is determined to be ~1.2 ps at RT. The calculated photocurrent intensity, obtained by solving the Maxwell wave equation and the coupled drift–diffusion/Poisson equation using the finite element method, is in good agreement with previously reported results. This work may provide a new approach for the material growth towards high-performance THz photoconductive antennas with high radiation power.
Funding Information
  • National Natural Science Foundation of China (61964003, GuiKeAD20238095, 20210217-9, XDB43000000)
  • The Science and Technology Base and Talent Special Project of Guangxi (61964003, GuiKeAD20238095, 20210217-9, XDB43000000)
  • Guilin Innovation Platform and Talent Plan (61964003, GuiKeAD20238095, 20210217-9, XDB43000000)
  • the Strategic Priority Research Program of the Chinese Academy of Sciences (61964003, GuiKeAD20238095, 20210217-9, XDB43000000)
  • the University-Enterprise Cooperation Program of School of Electronic Information and Modern Industry, Guangxi Normal University (61964003, GuiKeAD20238095, 20210217-9, XDB43000000)

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