Raman and photoluminescence spectra of Zn1-xCdxSe/Zn1-yMnySe: A diluted-magnetic-semiconductor superlattice

The luminescence spectrum of Zn1-xCdxSe/Zn1-yMnySe superlattices grown by molecular-beam epitaxy on (001) GaAs substrates shows quantum-well confinement and Zeeman shifts due to wave-function penetration into the barrier that are in excellent agreement with calculations using the transfer-matrix method based on the kp formalism. The new periodicity introduced by the superlattice causes zone folding of the acoustic branch, allowing modes with large q vectors to become Raman active. The Raman spectrum shows the folded acoustic phonons of superlattices with as few as ten periods. In addition to the excitonic Zeeman shifts, these magnetic superlattices exhibit the Raman-electron paramagnetic resonance of Mn2+ typical of the Mn-based diluted magnetic semiconductors.