Аннтотация

© 2018 SPIE.  We have investigated the influence of indium content (x) increase on spectral characteristics of In x Ga 1-x As photoconductor. To avoid the mismatch between crystalline parameters of In x Ga 1-x As and GaAs wafer we proposed to incorporate a step-graded metamorphic buffer layer. We showed that x increase strongly enhances THz emission and broadens THz spectrum of In x Ga 1-x As. Since no polarity rehearsal of the THz waveform occurs and electron diffusion mobility increases up to 90% with x increase we attribute the increase of THz intensity to photo-Dember effect contribution. The maximum efficiency of optical-to-THz conversion was obtained for In 0.72 Ga 0.28 As at optical fluence ∼0.01 μJ=cm 2 . The fabricated photoconductors can be used as promising photo-Dember or lateral photo-Dember THz emitters in pulsed THz spectroscopy and imaging, in particular, operating with long wave optical pump.