Contactless Electroreflectance Studies of Ultra-Dilute GaAs1-xBix Alloys: Article No. 035018

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 um) 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.