Nitrogen localized states in presence of bi-dimensional electron gas in heavily doped GaAs1-xNx

Abstract

We report a low-temperature photoluminescence spectra (LTPL) of GaAs1-xNx layers and 2 dimension electron gas (2DEG) GaAs1-xNx/AlGaAs modulation doped heterostructure grown on GaAs substrates by molecular beam epitaxy (MBE) with low nitrogen content [N]=21018cm-3. At low temperature PL spectra of GaAs1-xNx layers are governed by several features associate to the excitons bound to nitrogen complexes, these features disappear in (2DEG) GaAs1-xNx/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 to 300 K range for a laser power excitation P=6W/cm2.