Growth of III-V nitride films for optoelectronic devices

III-V nitrides semiconductor material system have wide bandgaps ranging from 3.4 eV to 5.8 eV and direct transition. Thus, they provides exciting possibilities to fabricate injection light emitting devices in visible and near ultra violet spectrum. However, nitrogen incorporation into the lattice site needs high growth temperatures, which limits the choice of substrates. Therefore, growth temperature needs to be reduced. We have developed a low pressure metalorganic vapor phase epitaxy (MOVPE) process using a modified in situ mixing in a vertical reactor. Triethylgallium and ammonia were used as sources of gallium and nitrogen, respectively. GaN films were grown on GaAs, alumina, and Si substrates at temperatures ranging from 600 degrees C to 700 degrees C and a system pressure of 79 Torr. Films were characterized by ellipsometry, x-ray diffraction, Raman spectroscopy, scanning electron microscopy, and Hall measurements. As grown films were found to be stoichiometric with hexagonal orientation, and n type with room temperature carrier concentration n = 8 x 10(16)/cm(3).