Surface segregation of indium atoms during molecular beam epitaxy of InGaAs/GaAs superlattices on [formula omitted] GaAs substrates

Abstract

We have investigated substrate off-angle dependence of surface segregation of In atoms during molecular beam epitaxy (MBE) of pseudomorphic In 0.08 Ga 0.92 As / GaAs superlattices (SLs) on ( n 1 1 ) A -oriented GaAs substrates ( n =3–5). Surface segregation length of the In atoms ( λ : 1/ e decay length of the In content profile along the growth direction) was characterized by high resolution X-ray diffraction (HRXRD) and low-temperature (11 K) photoluminescence (PL) measurements. λ obtained for the ( n 1 1 ) A SLs were 1.2–1.4 times longer than that ( λ = 1.57 nm ) for the simultaneously grown (1 0 0) SL, and the (4 1 1)A SL showed the longest λ of 2.16 nm. The obtained substrate off-angle dependence of the In segregation length is quite similar to the incorporation life-time ( τ c ) of Ga adatoms reported for MBE growth of GaAs on channeled (1 0 0) substrates, indicating that larger surface migration of Ga adatoms during MBE growth on ( n 1 1 ) A substrates causes enhanced surface segregation of In atoms in the ( n 1 1 ) A InGaAs system.