Intensive Terahertz Radiation from InXGa1-XAs due to Photo-Dember Effect

We have proposed and investigated InyGa1-yAs photoconductor grown by molecular-beam epitaxy on low-temperature step-graded metamorphic buffer. It exhibits superior bandwidth up to 6 THz and provides optical-to-terahertz conversion efficiency up to ~ 10−5 for rather low optical fluence ~ 40 μJ/cm2. The intensity of THz generation for the given structure is two orders higher than for lowtemperature grown GaAs due substantial contribution of photo-Dember effect.

Oscillations of electron–hole plasma in terahertz emitters

Oscillations of photogenerated electron–hole plasma in freestanding terahertz emitters are studied using the hydrodynamic analysis and Monte Carlo simulations. The pronounced plasma oscillations are obtained in an n-GaAs emitter in which the oscillations are initiated by the surface electric field. The plasma oscillations are also found in an n-InAs emitter in which the oscillations are induced by the photo-Dember effect.

Laser Terahertz Emission Spectroscopy of Graphene/InAs Junctions

ABSTRACTWe applied laser THz emission spectroscopy to study the effects of monolayer graphene on the THz emission from InAs. THz emission from graphene/InAs varies linearly with the laser excitation power in the low-intensity excitation regime. We found that unlike in graphene/SI-InP junctions, graphene and O2 adsorbates on graphene have no significant effect on the THz emission from graphene/InAs junctions because the THz radiation mechanism in InAs is by the photo-Dember effect, whereas for SI-InP is by the surge current effect. There is also a slight enhancement in the THz emission from both bare InAs and graphene/InAs by UV illumination, which is probably due to the additional photoexcited carriers by UV that somehow enhances the photo-Dember field.