Studies of band-gap differences in SiC polytypes
碩士 === 國立成功大學 === 物理研究所 === 81 === Silicon carbide froms dozens of different structures by stacking identical SiC double layers in different stacking sequences. The majority of the physical properties of SiC polytypes are very similar as t...
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Others |
| Language: | en_US |
| Published: |
1993
|
| Online Access: | http://ndltd.ncl.edu.tw/handle/66118033817495164884 |
| Summary: | 碩士 === 國立成功大學 === 物理研究所 === 81 === Silicon carbide froms dozens of different structures by
stacking identical SiC double layers in different stacking
sequences. The majority of the physical properties of SiC
polytypes are very similar as the environments of atoms are
identical up to the second nearest neighbour for all polytypes.
However, the band-gap different is as large as 0.9 eV. In the
present studies, we used the nearest-neighbour tight-binding
model which assumes the interatomic interactions are the same
for all the polytypes to calculate the band structures of SiC
polytypes. The large band-gap difference is obtained and the
band structure of the zincblende SiC is more reasonable than
those previously generated ones. It is found that the large
band-gap differece is due to the large variations in the first
conduction bands of differenr polytypes. The top valence bands
for different polytypes are almost the same. The physical
properties which do not involve excitations are therefore
expexted to be similar for different polytypes. Investigations
of the effect of the interatomic interactionson the band-gap
difference showed that the crucial factor is the pp.pi. inter-
action bbetween atoms.
|
|---|