Electromodulation spectroscopy of heavy-hole, light-hole, and spin-orbit transitions in GaAsBi layers at hydrostatic pressure

Abstract

GaAsBi layers of various Bi concentrations have been grown by molecular beam epitaxy on a GaAs substrate and studied by electromodulation spectroscopy (EM). Optical transitions related to heavy-hole (HH) and light-hole (LH) bands as well as the spin-orbit (SO) split-off band have been observed in EM spectra, and their energies have been found to be in very good agreement with theoretical predictions, which take into account the strain-related shifts obtained from the Bir-Pikus theory implemented to the electronic band structure of GaAsBi obtained after recent density functional theory (DFT) calculations for this alloy. The pressure coefficients for HH, LH, and SO transitions have been determined from photoreflectance measurements performed at various hydrostatic pressures and discussed.