Friday, June 1, 2018
Abstract-Photoconductive antennas based on epitaxial films In0.5Ga0.5As on GaAs (1 1 1)A and (1 0 0) substrates with a metamorphic buffer
K A Kuznetsov, G B Galiev, G Kh Kitaeva, V V Kornienko, E A Klimov, A N Klochkov, A A Leontyev, S S Pushkarev, P P Maltsev
The terahertz (THz) wave generation by the spiral photoconductive antennas fabricated on the low-temperature and high-temperature grown undoped and Si-doped InGaAs films is studied by the terahertz time-domain spectroscopy method. The InGaAs layers were grown by molecular beam epitaxy on GaAs substrates with (1 0 0) and (1 1 1)A crystallographic orientations utilizing step-graded InGaAs metamorphic buffer. The antennas are excited by radiation of Er-fiber laser at 1.56 μm wavelength in two regimes: with pulse durations of 2.5 ps or 100 fs. It is found that the THz wave generation is 3–4 times more effective in the case of InGaAs-based antennas on (1 1 1)A GaAs substrates as compared to the (1 0 0) substrates. Power-voltage characteristic of the LT-InGaAs antenna up to and beyond threshold breakdown voltage are reported.