270
9 Optical Properties
(a)
(b)
Fig. 9.10 a Absorption spectra of (In x Ga 1−x ) 2 O 3 alloy thin films on Al 2 O 3 , plotted as α 2 versus photon energy. b Band
edge determined from extrapolation of linear parts
(a)
GaAs
1.42
1.46
1.50
1.48
1.52
1.56
1.54
4
- 1
0.6
0.7
0.8
0.9
1.0
1.2
1.1
1.44
(b)
(c)
4
- 1
1.5
2.0
2.5
5
10
0
GaAs
E + 0
0
E 0
Fig. 9.11 a Absorption of GaAs close to the band gap at different temperatures. Adapted from [842]. b High-resolution
absorption spectrum of highly pure GaAs at T = 1.2 K in the exciton region. Dashed line is theory without excitonic
correlation. Adapted from [843]. c Absorption spectrum of GaAs at T = 21 K in the vicinity of the band gap. Adapted
from [842]
9 Optical Properties
(a)
(b)
Fig. 9.10 a Absorption spectra of (In x Ga 1−x ) 2 O 3 alloy thin films on Al 2 O 3 , plotted as α 2 versus photon energy. b Band
edge determined from extrapolation of linear parts
(a)
GaAs
1.42
1.46
1.50
1.48
1.52
1.56
1.54
4
- 1
0.6
0.7
0.8
0.9
1.0
1.2
1.1
1.44
(b)
(c)
4
- 1
1.5
2.0
2.5
5
10
0
GaAs
E + 0
0
E 0
Fig. 9.11 a Absorption of GaAs close to the band gap at different temperatures. Adapted from [842]. b High-resolution
absorption spectrum of highly pure GaAs at T = 1.2 K in the exciton region. Dashed line is theory without excitonic
correlation. Adapted from [843]. c Absorption spectrum of GaAs at T = 21 K in the vicinity of the band gap. Adapted
from [842]