SPIN-FLIP RAMAN-SCATTERING STUDIES OF DOPED EPITAXIAL ZINC SELENIDE

Raman scattering has contributed to the understanding of semiconductor materials at a fundamental level and has also proved powerful in the characterization of semiconductors, their alloys and heterostructures. This brief review will indicate some of the ways in which Raman spect roscopy has been applied in the study of II-VI semiconductors, with sp ecial attention to recent examples relevant to the application of ZnSe -based materials in optoelectronics. Tn particular, studies of electro n spin-flip Raman scattering in p-type ZnSe will be discussed which sh ow the presence of two distinct donor centres in highly doped p-type Z nSe:N; the two donors can be distinguished in spin-flip Raman scatteri ng experiments by their different g-values. The resonance behaviour of the two Raman signals confirms that they are associated with two diff erent donor centres and reveals a correlation between the localisation energy of an exciton at the neutral donor centre and the binding ener gy of the electron to the donor ion. Directions for future experiments will be indicated.