GROWTH AND CHARACTERIZATION OF GaAs1-xNx EPITAXIAL LAYERS

Raman scattering and photoluminescence properties of GaAs1-xNx epitaxial layers grown on GaAs and Ge substrates by means of metalorganic vapor phase epitaxy (MOVPE) have been investigated. Trimethylgallium (TMG), AsH3 and Dimethylhydrazine (DMHy) were used as precursors in the setup with horizontal reactor. The samples were grown at atmospheric pressure at temperature 5000C and varying the molar ratio between DMHy and the other precursors. Nitrogen in diluted GaAsN has been detected by Raman scattering through the observation of the nitrogen local vibrational mode at about 470 cm-1. Weak GaAs second order Raman features like TO and LO peaks are observed between 500 and 600 cm-1, evidencing alloy disorder. The photoluminescence (PL) properties have also been investigated on as grown samples. The PL peak energy of a GaAs1-xNx is 1.15 eV at 77 K, when the N content (x) is about 2.1 %.