ABSTRACT: Intense terahertz radiation was generated from femtosecond laser-irradiated InAs and GaAs layers on Si substrates. Results
show that InAs/Si and GaAs/Si films can be excited in reflection and transmission geometries. The InAs/Si film exhibited weaker
emission for both excitation cases but it will be more feasible as a spectroscopic THz source due to the absence of complex
spectral features in its emission spectrum. The GaAs/Si emission is characterized by Fabry–Perot oscillations but it is 90%
of that of p-InAs bulk crystal emission intensity in the reflection geometry. Excitation fluence measurements showed that
the InAs/Si film saturates easily due to the laser’s shallow penetration depth in InAs.
Applied Physics B 04/2012; 103(4):825-829. · 2.19 Impact Factor