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Silicon carbide is an interesting high-temperature large band gap
semiconquctor. it ispromising as a basical material for optoelectronic
devices . The optical properties of SiC have been studied by several authors.
The absrption coefficient of SiC 6H3 has been measured by Choyke and
Patrick up to 4.9 eV and by Makarov to 5.8 eV. Reflection spectra of 6H,
15R, and 3C SiC in the range 3.0 to 13 eV have been stidied in . The optical
constants of SiC 6H have been measured by reflectivity in the range 4 to 25
eV,
The energies of direct optical transitions between subbands in the
conduction band, resulting from confinement in a one dimensional superI,at,,tice,
have been measured in8sveral polytypes of SiC by absorption ' and
electroreflection (ER) '
The electron energy band structure (85) of SiC of1he1 halerite
structure (3C SiC) has been calculated by several 1tu4r2 ' . BS of
wurtzite modification of SiC have been calculated 1 in ' ' ' for 2H iC.
BS of 4H and 6H SiC has been calculated by the semiempirical
pseudopotential method at high-symmetry points of the Brillouin zone (BZ).
Tight binding calculations of 2H SiC show valence bands which agree with
experiment, but unrealistic conductive bands due to the restriction to nearest
neighbours in the Hamiltonian matrix
In this work we report the electroreflectance (ER) spectra of hexagonal
(4H and 6H) and cubic SiC measured in the range 1.0 to 5.6 eV. Values of
direct optical gps1ave been obtained from the ER spectra using a multiple
oscillator model ' . BS of SiC has been calculated by the first-principles
self-consistent linear muffin-tin orbital (LMTO-ASA) method (2H, 4H, and 6H
SiC) and by the semiempirical pseudopotential method (3C SiC). Calculated BS
parameters have been compared with experimental data measured in this work and
those available in the literature.
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