Analysis of mixed optical transitions in dilute magnetic AlAs/GaAs/GaMnAs quantum wells grown on high substrate index by molecular beam epitaxy

Abstract

© 2023 Elsevier B.V.In this study, we report the influence of high-index substrate orientation on the optical properties of dilute Mn containing a single quantum well (QW) structure grown by molecular beam epitaxy (MBE). The electronic band structure of the samples is calculated with finite element methods (FEM). Photomodulated reflectance (PR) spectroscopy is employed to determine the optical transition energies at room temperature. PR experimental results are analyzed with the Third Derivative Functional Form (TDFF) signal function. TDFF fitting shows that the optical transition starts below the fundamental GaAs bandgap energy for the samples grown on (3 1 1) B and (4 1 1) B-oriented substrates. Comparing TDFF fitting and calculated optical transition energies with FEM show that the optical transition occurs in type-I and type-II as direct and indirect transitions, respectively. Type-I and -II optical transitions are addressed concerning the electronic band structure of the sample grown on oriented substrates.