Contactless electroreflectance studies of ultra-dilute GaAs1−xBix alloys

Abstract

In this work we report a large effect due to relativistic corrections in the electronic structure of very dilute GaAs1−xBix (x < 0.0025) thick epitaxial layers. The variation of the spin–orbit split-off band for x as small as 0.0001 is reported. Very thick (2–3 µm) epilayers were grown by molecular-beam epitaxy to isolate the transitions between the conduction band and the spin–orbit split-off band from the epilayer and the substrate, using contactless electroreflectance. Thick epitaxial quality samples with precise control of the spin–orbit splitting are interesting for applications in spin-based electronics.