Optical properties of cadmium sulfide, zinc selenide, and zinc manganese selenide semiconductor films
Optical properties of CdS, ZnSe and (ZnMn)Se semiconductor films were investigated in the vicinity of their main absorption edge. Experimental transmission spectra of thin CdS platelets of thickness 1.2 [mu]m were theoretically fitted using a Fabry-Perot cavity and the source of the A[sub n=1] excitonic polariton damping dispersion was identified for temperatures between 2 and 180 K. For a given temperature the damping constant [Sigma]([omega]) is independent of frequency below the resonance frequency while it is detuning-dependent above the resonance. Below 70 K, [Sigma] was found to be constant below resonance and increased linearly above resonance. Above 70 K, the damping parameter increased exponentially both below and above resonance where it is dominated by the scattering of polaritons by optical phonons. The optical phonon and room temperature gap energies were equal to 38.01 MeV and 2.45a eV, respectively. The dielectric function and the lattice misfit induced strain in ZnSe and (ZnMn)Se films grown on (001) GaAs were investigated by room temperature spectroscopic ellipsometry. The bulk-like dielectric function of unstrained ZnSe films was determined for energies between 1.5 and 4.5 eV used to study the effects of strain on the top valence band at the origin of the Brillouin zone in thin ZnSe films. The top valence band splits into light and heavy holes bands and these subbands and the spin-orbit band shift towards lower energies. The coupling between the light hole and spin-orbit band induces an additional shift and broadening of the critical points. In (ZnMn)Se films the critical thickness is smaller than that of ZnSe, and the strain becomes tensile for film thicknesses above 0.5 [mu]m because of the difference in the thermal expansion coefficients between GaAs and (ZnMn)Se. The shift of the various bands is towards higher energies. The ZnSe/GaAs interface was identified as a 9 [angstrom] layer of Ga[sub 2]Se[sub 3].
- Research Organization:
- Maryland Univ., College Park, MD (United States)
- OSTI ID:
- 7236159
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CADMIUM SULFIDES
OPTICAL PROPERTIES
MANGANESE SELENIDES
ZINC SELENIDES
DIELECTRIC PROPERTIES
ELECTRON-PHONON COUPLING
L-S COUPLING
SEMICONDUCTOR MATERIALS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
CADMIUM COMPOUNDS
CHALCOGENIDES
COUPLING
ELECTRICAL PROPERTIES
INORGANIC PHOSPHORS
INTERMEDIATE COUPLING
MANGANESE COMPOUNDS
MATERIALS
PHOSPHORS
PHYSICAL PROPERTIES
SELENIDES
SELENIUM COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS
360606* - Other Materials- Physical Properties- (1992-)