Abstract
We have investigated by photoreflectance spectroscopy (PR) the optical properties of GaAs1-xNx/GaAs heterostructures (thin films) grown by Molecular beam epitaxy (MBE) on (001) oriented GaAs substrates. High resolution X ray Diffraction (HRXRD) has been achieved to determine the nitrogen fraction (of about 0.45-2.4%) incorporated into GaAs. We have studied the effect of the nitrogen incorporation on the conduction band of GaAs by PR measurements which is confirmed by using the band anticrossing model. The incorporation of nitrogen appears to decrease the band gap energy and increase the emission wavelength. The reduction of energy is due to the splitting of the conduction band in two subbands E- and E+ which depends on the nitrogen composition. Since, more the concentration of nitrogen increases, more the energy of the band gap decreases.