Ultra-fast domain formation in a semiconductor superlattice

Presents experimental evidence for ultra-fast domain formation in a semiconductor superlattice. An InGaAs/InAlAs superlattice device was mounted in a corner cube. The superlattice device showed a region of negative differential conductance in the current-voltage characteristic for voltages larger than an onset voltage. When the superlattice device was irradiated with radiation smaller than 1.2 THz, the onset voltage shifted, with increasing THz radiation power, to lower voltages. Taking an analysis based on a drift-diffusion model into account, we suggest that dipole domains form within about 400 fs.