TEM dislocations characterization of InxGa1−xAs/InP (100) (x=0.82) on mismatched InP substrate

Dislocation behavior in In_xGa_1−xAs/InP (100) (x=0.82) grown by low pressure chemical vapor deposition (LP-MOCVD) at temperature about 430 °C was analyzed thoroughly by [110] cross-section transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and high resolution transmission electron microscopy (HRTEM). The 2% lattice mismatch between InP (100) and In_xGa_1−xAs (x=0.82) results in various types of defects such as stacking faults as well as 60° and 90° threading dislocations. Very high density of threading dislocation (TD) was shown in the In_xGa_1−xAs (x=0.82) epilayer. The epilayer was incompletely strain relaxed by the formation and multiplication of MDs.

Highlights

• In_xGa_1−xAs (x=0.82) detectors with the cut-off wavelength of 2.5 μm grown by low pressure chemical vapor deposition (LP-MOCVD).

• The defects structure of a ternary epitaxial layer as discussed deeply.

• Various types of defects such as stacking faults as well as 60° and 90° threading dislocations were identified near interface.

• The plastic relaxation of strained heterostructures was incompletely strain relaxed by the formation and multiplication of misfit dislocations (MDs).

Source:Current Applied Physics

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