Microstructure and misfit dislocation behavior in InxGa1-xAs/InP heteroepitaxial materials grown by low pressure metal organic chemical vapor deposition (LP-MOCVD) were analyzed by high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy and Hall effect measurements. To optimize the structure of In_0.82Ga_0.18As/InP heterostructure, the In_xGa_1-xAs buffer layer was grown. The residual strain of the In_0.82Ga_0.18As epitaxial layer was calculated. Further, the periodic growth pattern of the misfit dislocation at the interface was discovered and verified. Then the effects of misfit dislocation on the surface morphology and microstructure of the material were studied. It is found that the misfit dislocation of high indium (In) content In_0.82Ga_0.18As epitaxial layer has significant influence on the carrier concentration.

In order to improve the quality of detector, InxGa1-xAs (x=0.82) buffer layer has been introduced in In_0.82Ga_0.18As/InP heterostructure. Dislocation behavior of the multilayer is analyzed through plane and cross section [110] by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The dislocations are effectively suppressed in InxGa1-xAs (x=0.82) buffer layer, and the density of dislocations in epilayer is reduced obviously. No lattice mismatch between buffer layer and epilayer results in no misfit dislocation (MD). The threading dislocations (TDs) are directly related to the multiplication of the MDs in buffer layer.