Comparative study of terahertz radiation from n-InAs and n-GaAs

We have studied terahertz (THz) emissions from n-InAs and n-GaAs using an ensemble Monte Carlo method. Our simulations indicate that higher amplitude THz waves from n-InAs, compared with those from n-GaAs, result from the difference in the radiation mechanisms between these two samples and are not completely dependent on the most commonly recognized fact: lighter electron effective mass in n-InAs. The excitation-wavelength-dependent and doping-level-dependent THz emissions from n-InAs are found to be quite different from those from n-GaAs. The corresponding mechanisms are analyzed by the introduction of a weighted electric field, which is weighted by the photogenerated carrier density in a semiconductor. The simulated results are in good qualitative agreement with experimental observations from other authors.