Microscopic structure and optical properties of GaAs1-xN x/GaAs(001) interface grown by metalorganic vapor phase epitaxy

Abstract

We have investigated the structure and optical properties of GaAs 0.97N0.03/GaAs produced by metalorganic vapor phase epitaxy grown on GaAs surface at 520-550°C. Using cross-sectional transmission electron microscopy and photoluminescence spectroscopy (PL), we show the presence of a 5-6-nm-thick nitrogen-rich interfacial region. The nitrogen composition near the interface is twice higher (x=0.038) than that of the bulk epilayer (x=0.016). PL data shows two peaks located at 1.05 and 1.18 eV associated to the interfacial region and the bulk layer, respectively. We discuss several mechanisms of surface enrichment of nitrogen that occurred during the first stage of GaAsN growth. © 2002 American Institute of Physics.