Structural investigation of InGaAsN films grown on pseudo-lattice-matched InGaAs substrates by metalorganic vapor phase epitaxy

The use of the nearly lattice-matched InxGa1−xAs pseudo-substrate has been explored for the growth of InxGa1−xAs1−yNy with higher In (x) contents by metalorganic vapor phase epitaxy (MOVPE). As compared with the quality of high In-containing In0.3Ga0.7As0.98N0.02 films grown directly on GaAs substrates, the growth on In0.2Ga0.8As pseudo-lattice-matched substrates yielded good structural quality films. The number of misfit dislocations investigated by cross-sectional transmission electron microscopy was found to be reduced in the InGaAsN grown layer. Furthermore, higher optical quality In0.3Ga0.7As0.98N0.02 films with the bandgap of 1.01 eV were grown on the In0.2Ga0.8As pseudo-lattice-matched substrate. This study shows that the use of the InxGa1−xAs pseudo-lattice-matched substrate is an effective method to fabricate a thick lattice-matched InGaAsN layers with higher optical and structural qualities necessary for the development of the multijunction (MJ) solar cells.