A comparison of the structural quality of high-in content InGaAsN films grown on InGaAs pseudosubstrate and on GaAs substrate

The use of an InGaAs buffer layer was applied to the growth of thick In_xGa_1-xAs_1-yN_y layers with higher In contents (x > 30%). In order to obtain the lattice-matched InGaAsN layer having the bandgap of 1.0 eV, the In_0.2Ga_0.8As was chosen. In this work, the In_{0 3}Ga_0.7As_0.98N _0.02 layers were successfully grown on closely lattice-matched In_0.2Ga_0.8As buffer layers (InGaAsN/InGaAs). Structural quality of such layers is discussed in comparison with those of the In _0.3Ga_0.7As_0.98N_0.02 layers grown directly on the GaAs substrate (InGaAsN/GaAs). Based on the results of transmission electron microscopy, the misfit dislocations (MDs), which are located near the InGaAsN/GaAs heteroepitaxial interface, are visible by their strain contrast. On the other hand, no generation of the MDs is evidenced in the InGaAsN layer grown on the In_0.2Ga_0.8As pseudosubstrate. Our results demonstrate that a reduction of misfit strain though the use of the pseudosubstrate made possible the growth of high In-content InGaAsN layers with higher crystal quality to extend the wavelength of InGaAsN material.