J. K. Morrod

Exciton?photon coupling in a ZnSe-based microcavity fabricated using epitaxial liftoff

We report the observation of strong exciton–photon coupling in a ZnSe-based microcavity fabricated using epitaxial liftoff. Molecular beam epitaxial grown ZnSe/Zn0.9Cd0.1Se quantum wells with a one wavelength optical length at the exciton emission were transferred to a SiO2/Ta 2O5 mirror with a reflectance of 96% to form finesse matched microcavities. Analysis of our angle-resolved transmission spectra reveals key features of the strong coupling regime: anticrossing with a normal mode splitting of 23.6 meV at 20 K, composite evolution of the lower and upper polaritons and narrowing of the lower polariton linewidth near resonance. The heavy-hole exciton oscillator strength per quantum well is also deduced to be 1.78 × 10 13 cm −2 . (Some figures in this article are in colour only in the electronic version)

Study of structural transition from metastable zinc blende to rocksalt crystal in molecular beam epitaxy MgS∕ZnSe∕GaAs multilayer system

The stable crystal structure of magnesium sulfide (MgS) is rocksalt. However, the metastable zinc-blende structure is obtained when MgS is deposited by molecular beam epitaxy (MBE) on (001) zinc-blende substrates with a relatively small misfit. In the present work, the zinc blende to rocksalt phase transition is analyzed in MgS∕ZnSe∕GaAs multilayer samples grown by MBE with different MgS layer thicknesses. By x-ray diffraction and transmission electron microscopy methods, a partial nucleation of MgS rocksalt is evidenced and correlated to the presence of stacking faults at the bottom interface. The unexpected coexistence of both rocksalt and zinc-blende MgS structural phases is discussed.

Surface acoustic wave mediated exciton dissociation in a ZnCdSe/LiNbO3 hybrid

By making use of epitaxial lift-off, ZnCdSe quantum wells are transferred onto a LiNbO3 substrate in order to employ its enhanced piezoelectric properties. The photoluminescence emission of this hybrid structure is characterized and the influence of a surface acoustic wave on the free exciton and bound exciton emission is investigated. Finally, two counterpropagating surface acoustic waves are launched leading to a decrease in the acoustic wave mediated exciton dissociation.

ZnSe-based microcavity fabricated using epitaxial liftoff

We present key features of the strong coupling regime in a ZnSe-based microcavity; anticrossing with a normal mode splitting of 23.6 meV at 20 K; narrowing of the lower polariton linewidth near resonance; and composite evolution of the cavity-polaritons. The heavy-hole exciton oscillator strength, fosc= 1.78 times 1013 cm-2 is also deduced.

Angle resolved transmission spectroscopy of ZnSe based microcavities fabricated using epitaxial liftoff technique

We demonstrate level-repulsion of exciton-polaritons in ZnSe/Zn_0.9Cd_0.1Se quantum wells transferred to SiO₂/Ta₂O₅ mirrors using epitaxial liftoff to fabricate our microcavities. The heavy-hole exciton oscillator strength is calculated to be 5.7 times10¹² cm^-2 .