INVESTIGATION OF STRAIN IN II-VI SEMICONDUCTOR SUPERLATTICES USING ELECTRON-PARAMAGNETIC-RESONANCE OF MN++

We explore the possibility of using electron paramagnetic resonance (E PR) of Mn++ for measuring uniaxial strain in II-VI superlattices. This work is motivated by the fact that the EPR spectrum of Mn++ is very s trongly affected by crystalline fields. Changes in a crystalline field which arise from strain are thus automatically expected to have a pro found effect on tile EPR spectrum. Consistent with this expectation, w e have observed giant crystal field splittings of Mn++ EPR lines in Zn Te/MnTe, CdTe/MnTe, and ZnTe/MnSe superlattices. The EPR spectra obser ved in these systems are ascribed to isolated Mn++ ions diffused into the ZnTe or the CdTe layers from tile respective MnTe or MnSe layers. In addition to providing precise information on the magnitude and the sign of strain produced by lattice mismatch between the superlattice c onstituents, we show that the EPR spectrum also provides a direct meas ure of strain fluctuations in the layered medium.