As 4 pressure dependence of surface segregation of indium atoms during molecular beam epitaxy of In0.08Ga0.92As/GaAs superlattices on (411)A GaAs substrates

Abstract

As 4 pressure dependence of surface segregation of In atoms during molecular beam epitaxy (MBE) growth of pseudomorphic In0.08Ga0.92As/GaAs (7.5 nm/11.2 nm) superlattices (SLs) on (411)A GaAs substrates was investigated by high resolution x-ray diffraction (HRXRD) and 12 K photoluminescence measurements. Surface segregation lengths of In atoms (λ: 1/e decay length of In content profile along the growth direction) determined by HRXRD decrease with increasing V/III ratio for both the (411)A and simultaneously grown (100) SLs. λ for the (411)A SL grown under V/III (As4/Ga) pressure ratio of 10 was 2.32 nm, which is 1.4 times larger than that for the (100) SL, while λ was almost the same for both the (411)A and (100) SLs grown under V/III=30. With decreasing V/III ratio, In surface segregation increased, and InGaAs/GaAs interface flatness was improved in the (411)A InGaAs/GaAs SLs. Reduced As4 pressure results in enhanced surface segregation of In atoms as well as enhanced surface migration of In atoms during MBE growth of the (411)A InGaAs/GaAs SLs.