Impact ionization in low-band-gap semiconductors driven by ultrafast THz excitation: beyond the ballistic regime

Abstract

Using two-dimensional THz spectroscopy in combination with numerical models, we investigate the dynamics linked to carrier multiplication caused by high-field THz excitation of the low-gap semiconductor InSb. In addition to previously observed dynamics connected with quasi-ballistic carrier dynamics, we observe other spectral and temporal features that we attribute to impact ionization for peak fields above 60 kV/cm, which continue up to the maximum investigated peak field of 430 kV/cm. At the highest fields we estimate a carrier multiplication factor greater than 10 due to impact ionization, which is well-reproduced by a numerical simulation of the impact ionization process which we have developed.

arXiv comment25 pages, 5 figures

References in corpus (6)

• Spintronics: Fundamentals and applications
• Impact ionization in InSb probed by THz-pump THz-probe spectroscopy
• Observation of Nonequilibrium Carrier Distribution in Ge, Si and GaAs by Terahertz-pump--Terahertz-probe Measurements
• Ballistic superconductivity and tunable $\pi$-junctions in InSb quantum wells
• 2D THz spectroscopic investigation of ballistic conduction-band electron dynamics in InSb
• Beyond the effective mass approximation: predictive theory of the nonlinear optical response of conduction electrons

Cited by in corpus (1)

• Roles of band gap and Kane electronic dispersion in the THz-frequency nonlinear optical response in HgCdTe