The effect of strain and spatial Bi distribution on the band alignment of GaAsBi single quantum well structure

• Published in: Physica. B, Condensed matter Condensed matter, 2021-02, Vol.602, p.412487, Article 412487
• Main Authors: Gunes, M., Donmez, O., Gumus, C., Erol, A., Alghamdi, H., Alhassan, S., Alhassni, A., Alotaibi, S., Schmidbauer, M., Galeti, H.V.A., Henini, M.
• Format: Article
• Language: English
• Subjects: Band gap; Band offset; Barrier layers; Bismide quantum well; Composition; Conduction bands; Crystals; Excitation; Indirect transition; Line spectra; Low temperature; Mathematical analysis; Optical properties; Optical transition; Photoluminescence; Quantum dots; Quantum wells; Studies; Valence band; Valence band anticrossing model
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2020.412487

The band line-up and band offset calculations of GaAs0.978Bi0.022/GaAs single quantum well with spatial changes of Bi composition were reported. The spatial Bi profile and a certain amount of the Bi composition in the barrier layer were determined by HR-XRD measurements. Virtual Crystal Approximation and Valence Band Anti-Crossing models were used including strain effects to obtain conduction and valence band edge shifts with Bi incorporation. Photoluminescence (PL) measurements were performed at a low temperature of 8 K as a function of excitation intensity. The PL spectra have shown asymmetric line shapes, which were fitted with different Gaussian functions. Comparing experimental PL results with calculated band edge energies, it was found that optical transition is a type I under low intensity excitation while the optical transition is switched from type I to type II due to the spatial changes in Bi concentrations. The band offsetsΔEc/ΔEv were also determined. •GaAsBi single QW structure was grown by MBE.•Actual Bi content distribution was determined in the structure.•Optical transitions at low temperature have been deeply investigated under low andhigh excitation power by PL experiment.•Optical transitions are identified as type-I under low excitation intensity and type-II under high excitation intensity•Band alignment was determined by using experimental results taking into account two different approaches such as Virtual Crystal Approximation (VCA) and Valence Band Anti-Crossing (VBAC) models.•The band offsets ΔEc /ΔEv found to be as ~44 meV/214 meV.