Spin-flip Raman scattering studies of II–VI heterostructures

Abstract

Spin-flip Raman (SFR) scattering is now an established technique for the investigation of semiconductor heterostructures. Because the scattering is resonantly enhanced when the laser is adjusted to coincide with the appropriate excitonic transition, the technique has high sensitivity. It is also highly selective, since the resonance enhancement occurs at different wavelengths for scattering by carriers confined under different circumstances. For electrons, the SFR spectra enable the g-factor to be determined thus providing tests of band structure theories. The g-factor is sensitive also to quantum confinement, when it may become anisotropic. In the case of holes, the higher angular momentum ( J= 3 2 ) makes the SFR spectra highly dependent on the state of strain of the material. Spin-flip signals from localised excitons can also be detected. Such signals enable the electron–hole exchange interactions to be determined: and are thus a sensitive probe of the localisation properties of the exciton, for example in quantum dots of differing sizes. Recent developments will be reviewed to illustrate how the technique can be used to investigate the physics and materials issues associated with II–VI structures.