MOVPE growth and optical investigations of InGaPN alloys

InGaPN alloy films were grown on GaP (0 0 1) substrates by metalorganic vapor phase epitaxy (MOVPE) at 635 °C using trimethylgallium (TMGa), trimethylindium (TMIn), PH₃ and 1,1-dimethylhydrazine (DMHy) as the precursors of Ga, In, P and N, respectively. For the fixed combination of TMGa, PH₃ and TMIn flows, the composition control of In_xGa _1-xP_1-yN_y was achieved simply by changing the molar flow ratio of DMHy to the total group V sources, giving y=0-8.7% and x=17.6%. The grown films show a systematic red shift of the photoluminescence (PL) peak energy with increasing N content. On the other hand, with increasing the TMIn molar flow while the other flows were fixed, the N incorporation is much affected by the TMIn flow due to some reaction kinetics. In fact, the N content was decreased from y=2.6% to 1.6% while the In content was increased from x=0 to 10.9%. As a result, the apparent blueshift of the PL peak energy for this growth series is due to the reduction of N incorporation with increasing TMIn flow. The lattice-matched In_xGa _1-xP_1-yN_y (x=17.6%, y=7.4%) film showed an excellent structural and optical quality in spite of the relatively high N content.