On the origin of carrier localization in AlInAsSb digital alloy

【摘要】 We compared the photoluminescence（PL） properties of Al In As Sb digital alloy samples with different periods grown on Ga Sb（001） substrates by molecular beam epitaxy. Temperature-dependent S-shape behavior is observed and explained using a thermally activated redistribution model within a Gaussian distribution of localized states. There are two different mechanisms for the origin of the PL intensity quenching for the Al In As Sb digital alloy. The high-temperature activation energy E₁ is positively correlated with the interface thickness, whereas the low-temperature activation energy E₂ is negatively correlated with the interface thickness. A quantitative high-angle annular dark-field scanning transmission electron microscopy（HAADF-STEM） study shows that the interface quality improves as the interface thickness increases. Our results confirm that E₁ comes from carrier trapping at a state in the In Sb interface layer, while E₂ originates from the exciton binding energy due to the roughness of the Al As interface layer.更多还原

【Abstract】 We compared the photoluminescence（PL） properties of Al In As Sb digital alloy samples with different periods grown on Ga Sb（001） substrates by molecular beam epitaxy. Temperature-dependent S-shape behavior is observed and explained using a thermally activated redistribution model within a Gaussian distribution of localized states. There are two different mechanisms for the origin of the PL intensity quenching for the Al In As Sb digital alloy. The high-temperature activation energy E₁ is positively correlated with the interface thickness, whereas the low-temperature activation energy E₂ is negatively correlated with the interface thickness. A quantitative high-angle annular dark-field scanning transmission electron microscopy（HAADF-STEM） study shows that the interface quality improves as the interface thickness increases. Our results confirm that E₁ comes from carrier trapping at a state in the In Sb interface layer, while E₂ originates from the exciton binding energy due to the roughness of the Al As interface layer.更多还原