Transient THz photoconductivity in dynamically screened InGaN/GaN quantum wells

Using optical pump - THz probe spectroscopy we reveal complex ultrafast photoconductivity dynamics in InGaN/GaN quantum wells under dynamical screening conditions, where, at sufficiently high excitation densities, the photo-generated carriers fully screen the initial internal field of 3 MV/cm. The THz photoconductivity spectra contain features of both localized and free charges.