Strong coupling between bi-dimensional electron gas and nitrogen localized states in heavily doped GaAs_(1-x)N_x structures

摘要

We report a low-temperature photoluminescence spectra (LTPL) of GaAs_(1-x)N_x layers and two-dimension electron gas (2DEG) GaAs_(1-x)N_x/AlGaAs modulation doped heterostructure grown on GaAs substrates by molecular beam epitaxy (MBE) with low nitrogen content [N] =2 x 10~(18) cm~(-3). At low temperature, PL spectra of GaAs_(1-x)N_x layers are governed by several features associate to the excitons bound to nitrogen complexes, these features disappear in (2DEG) GaAs_(1-x)N_x/AlGaAs modulation doped heterostructure and the PL peak energy decrease with the laser power excitation. This effect is explained by the strongly coupling of the (2DEG) fundamental state with the nitrogen localized states. An activated energy of about 55 meV is deduced by photoluminescence measurements in the 10-300 K range for a laser power excitation P = 6 W/cm~2.