Influence of growth temperature and V/III ratio on the optical characteristics of narrow band gap (0.77Â eV) InN grown on GaN/sapphire using pulsed MOVPE

In this study, we report on the pulsed metalorganic vapor phase epitaxy (MOVPE) of InN as well as the optical and electronic properties of the films as a function of V/III ratio and growth temperatures. The growth of InN films was conducted utilizing a vertical reactor with TMIn and NH3 as the In- and N-precursors, respectively. Metallic droplet-free InN films were achieved on GaN/sapphire template in a pulsed MOVPE mode with low V/III ratio condition. In the pulsed growth mode, NH3 was constantly flowing while the TMIn was sent into the reactor chamber for a 36-s pulse and then it bypassed the reactor chamber for an 18-s pulse for a total cycle time of 54 s. At a growth pressure of 200 Torr, the effects of growth temperature (510-575 °C) and V/III ratio (12,460-17,100) on the photoluminescence (PL) transitions were investigated. Morphological evolution as well as the electrical quality of the overgrown films have also been studied for the given growth conditions.