Influence of band structure and intrinsic carrier concentration on the THz surface emission from InN and InAs
We investigate the band structure effects on the terahertz (THz) electric field emission from unbiased InN and InAs surfaces using the ensemble Monte Carlo (MC) simulation method. It is shown that the nonparabolicity of the central conduction band valley and the energy separations between the central and satellite valleys are crucial parameters to provide a high efficiency of THz surface emitters. The THz emission from InN and InAs surfaces exposed to femtosecond laser pulses are compared over a wide range of photon energies from 0.85 eV (λ = 1550 nm) up to 1.55 eV (λ = 800 nm). We also demonstrate that the relatively high intrinsic carrier concentration of InAs (~8 × 1014 cm−3) has a negligibly small effect on the THz surface emission.