Observation of resonant and stimulated Raman scattering in ZnSe/CdSe quantum wells grown by atomic layer epitaxy

Abstract

This letter reports the successful growth of short period (ZnSe)4/CdSe4 strained layer superlattices on (100) GaAs surface by atomic layer epitaxy. The superlattice was characterized by x-ray diffraction and Raman scattering. Superlattice period was calculated from the satellite peaks and was in good agreement with the expected value. 2LO Raman scattering in resonance with the E1h exciton level was observed. Experimental exciton energy was compared with the one calculated in a finite-square-well model. A Raman line due to stimulated Raman scattering was also observed.

Suppression of lateral fluctuations in CdSe-based quantum wells

“…Values in the range of 10%-30% have been suggested by various authors. [13][14][15][16] The larger value of 30% would be in better agreement with our QW results.…”

Chapter 5 Optical Properties of Excitons in ZnSe-based Quantum Well Heterostructures

“…The remarkable overall agreement between calculated and measured transition energies supports the choice of band parameters (Table I) and exciton binding energies used here. Many theoretical and experimental studies of excitons in ZnCdSe/ZnSe MQWs have used quite different values for the conduction and valence band effective masses, deformation potentials, and band offsets (Ding et al, 1990b;Ding et al, 1992;Pelekanos et al, 1992b;Lozykowsky and Shastri, 1992;Alonso et al, 1992;Ding et al, 1993;Chung et al, 1993;Ren et al, 1994;Young et al, 1994;Cingolani et al, 1995;Pellegrini et al, 1995;Liaci et al, 1995) leading to slightly different results. The major problem in the eigenstate calculations is the interplay between the band offset expected for the bulk, unstrained materials and the effect of tetragonal strain field on the band extrema in determining the actual total band discontinuities.…”

“…The spread of these determinations thus depends on the choice of the effective masses, and structural parameters for the strain evaluation, and, in most cases, on the poor assessment of the well width and composition. On the other hand, the theoretical prediction of the offset (Chung et al, 1993;Ren et al, 1994) suffers the typical indetermination of band structure calculations which is of the order of several tens of meV.…”

Resonant Raman scattering and photoluminescence enhancement in ZnCdSe quantum wells

“…4-6 A few works reporting this phenomenon in II-VI QWs have recently appeared in the literature. 7,8 In this work, we report two types of resonance effects in the emission spectra of Zn 1Ϫx Cd x Se QWs: RRS and excitonic photoluminescence ͑PL͒ enhancement produced by the resonant absorption of the exciting photons with the fundamental transition of a QW. Furthermore, the coincidence between the exciton binding energy and the longitudinal optical ͑LO͒ phonon energy contributed to an important additional enhancement of RRS.…”