Abstract
We report on the role of AlSb material in the reduction of threading dislocation density (TDD) in the GaSb/AlSb/GaAs system. The AlSb layers were grown using low-temperature (LT) MBE, exploiting the interfacial misfit (IMF) dislocation array. AlSb layers with four different thicknesses in the range of 1–30 nm were investigated. The results showed the inhibiting role of LT-AlSb layers in the reduction of TDD. Values of TDD as low as 2.2 × 106 and 6.3 × 106 cm−2 for samples with thin and thick AlSb layers were obtained, respectively. The filtering role of AlSb material was proven despite the IMF-AlSb/GaAs interface’s imperfectness caused by the disturbance of a 90° dislocation periodic array by, most likely, 60° dislocations. The dislocation lines confined to the region of AlSb material were visible in HRTEM images. The highest crystal quality and smoother surface of 1.0 μm GaSb material were obtained using 9 nm thick AlSb interlayer. Unexpectedly, the comparative analysis of the results obtained for the GaSb/LT-AlSb/GaAs heterostructure and our best results for the GaSb/GaAs system showed that the latter can achieve both higher crystal quality and lower dislocation density.
Highlights
Gallium arsenide has many well-documented advantages, which make it the most commonly used substrate in the optoelectronic devices operating in the near-infrared spectral range [1,2,3]
GaSb/AlSb/GaAs material system is influenced by the growth conditions and thickness of the material system is influenced by the growth conditions and thickness of the AlSb layer
Vector, which corresponds to the observed 90◦ dislocations. These additional dislocations detected at the AlSb/GaAs interface could be responsible for the higher threading dislocation density (TDD) in GaSb/LT-AlSb/GaAs structure
Summary
Gallium arsenide has many well-documented advantages, which make it the most commonly used substrate in the optoelectronic devices operating in the near-infrared spectral range [1,2,3]. By applyingthis an relaxation additional mode either by optimizing the growth conditions or by applying an additional buffer in et a buffer in a GaSb/GaAs system [17,18,19,20,21] The latter approach has shown significant promise. The authors concluded that both low-temperature growth at promoted the reduction of threading dislocations They obtained an about four times lower TDD of. The aforementioned information does not provide an explanation the role theofAlSb in the process of TDD reduction in GaSb/LT-AlSb/GaAs system. Theofmain focus this layer paperplays is to in the process of TDD reduction in.
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