Optical spectroscopy of GaN grown by metalorganic vapor phase epitaxy using indium surfactant

The effect of In surfactant during metalorganic vapor phase epitaxial growth on sapphire substrates on the properties of GaN layers is studied using time-resolved photoluminescence, cathodoluminescence, and scanning electron microscopy. The samples are divided into two groups, where hydrogen and nitrogen, respectively, have been used as a carrier gas during growth. It is shown that In-doped samples have a lower dislocation density, a narrower photoluminescence linewidth, and a longer free exciton lifetime. The influence of indium is stronger for GaN layers grown in nitrogen-rich conditions. The improvements of structural and optical properties are attributed to the effect of In on dislocations.