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Cadmium Oxide
Crystal: CdO
Structure: NaCl
Usually nonstoichiometric with Cd in excess: n-type deg. semiconductor; see Refs.1-3
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Cohesive energy: |
eV |
Lattice parameter: |
Å |
Energy: |
g/cm3 |
Stiffness constants: in 1011 dynes/cm2, at room temperature
c11:
c12:
c44:
Compressibility (in 1011 dynes/cm2): 1.32*1012 (Ref.4) ?? Also: 0.88*1012 (Ref.5) ??
Poisson ratio:
Debye temperature: 279 K
Melting temperature: ° C
Phonon spectrum discussed by:
Transverse optic phonon T0 (k=0): 262±3 cm-1
Longitude optic phonon L0 (k=0): 478±25 cm-1
Plasma frequency: ~2400 cm-1 (this low energy must correspond to some specific carrier density; the bulk plasmon will be much higher)
Gruneissen constant:
Ratio e*/e:
Photoelastic constants:
p11:
p12:
p44:
Band gap:
direct: 2.28 eV. at 100 ° K. for
indirect: 0.84 eV. at 100K. for
G 1-S 3 (Ref.6), 1.09 eV. at 100K. for G 1-L3 (Ref.6)
Gap: eV.
First exciton: eV.
Plasmon (eV.): 22.8 (bulk) (Ref.7), 15.9 (surface)
Band structure :
UV reflectance data:
J.L. Freeouf, Far Ultraviolet reflectance of II-IV compounds and correlation with the Penn-Philips Gap, Phys. Rev. B7, 3810 (1973)
Self cons. band structure:
J.C. Boettger, A.B. Kunz, Ab initio energy bands for CdO, Phys. Rev. B27, 1359 (1983)
Static dielectric constant: 18.1±2.5
Optic dielectric constant: 5.4
m
= 2.49 (Winchell & Winchell)e
(¥ )= 6.2
Electron mobility:
Hole mobility:
Polaron coupling constant:
a = ~1.02 ( for m*=1 )Effective mass: conduction band:
valence band:
Electron affinity: ( in eV., from bottom of conduction band under vacuum)
Spin-orbit coupling: ( valence band)
Cation polarisation: Å-3
Anion polarisation: Å-3
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Other information:
CdO: x-ray analysis of ionicity:
Radii: Cd 1.24±0.05 Å O 1.25±0.05 Å
Charge: Cd (+1.7±0.2)
Ref.: E. Rantavuori, M. Linkoaho and R. Kuoppala, The ionicity of CdO by x-ray powder diffraction at 80K, Phys. Scripta 16, 161 (1977)
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References:
1. H. Finkenrath, W. Waidelich, Der Einfluss der Gitterschwingungen auf die Ultrarot-Reflexion von CdO, Sol. St. Comm. 5, 875 (1967)
2. Sol. St.Comm. 7, 11 (1969)
3. K.H. Rieder, M. Ishigarne and L. Genzei, Infrared absorption by coupled surface-phonon-surface-plasmon modes in microcrystals of CdO, Phys. Rev. B6, 3804 (1972)
4. Parodi
5. Lewiz, Perey (1966)
6. F. Koffyberg Thermoreflectance spectra of CdO: Band gaps and band population effects, Phys .Rev. B13, 4470 (1976)
7. R.L. Hengehold, F.L. Pedrotti, Plasmon excitation energies in ZnO, CdO, MgO, J. Appl. Phys. 47, 287 (1976)
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