Spin-flip Raman spectroscopy of nitrogen acceptors in ZnSe layers with different biaxial strains

Resonant spin-flip Raman scattering (SFR) was used to investigate systematically the effects of strain on the J = 3/2 spin states of nitrogen acceptors in p-type ZnSe grown on GaAs. Specimens from several MBE and MOVPE sources were studied and, by choosing specimens with different thicknesses of ZnSe, the in-plane biaxial strain could be chosen to be tensile or compressive, according to the extent of relaxation. For large tensile or large compressive strain, the acceptor states that lead to scattering are, respectively, the light- and heavy-hole states, which can be distinguished by the very different anisotropy of the corresponding SFR signals as the direction of the magnetic field is altered. The investigation also included specimens with a range of intermediate layer thicknesses for which the strain splitting of the hole states is comparable with the Zeeman splitting. In this case the field-induced lh/hh mixing is significant and the spectra are very sensitive to the exact value of the strain. The spin-Hamiltonian parameters κ + ̃(= -0.50 ± 0.05) and q̃(= -0.05 ± 0.01) were determined accurately by using specimens with small strains.