The temperature dependence of the optical‐absorption edge (Urbach edge) of GaAs is measured in semi‐insulating and n‐type GaAs (n=2×1018 cm−3) over the temperature range from room temperature to 700 °C. Both the optical absorption and the temperature are measured using a diffuse reflectance technique. The characteristic energy of the exponential absorption edge is found to increase linearly with temperature, from 7.5 meV at room temperature to 12.4 meV at 700 °C, for semi‐insulating GaAs. The temperature dependent part of the width of the Urbach edge for semi‐insulating GaAs is six times smaller than predicted by the standard theory where the edge width is proportional to the phonon population.
REFERENCES
1.
2.
3.
W.
Sritrakool
, V.
Sa-yakanit
, and H. R.
Glyde
, Phys. Rev. B
33
, 1199
(1986
);4.
G. D. Cody, in Semiconductors and Semimetals, edited by J. I. Pankove (Academic, New York, 1984), Vol. 21, Part B, Chap. 2.
5.
6.
H. C.
Casey
, D. D.
Sell
, and K. W.
Wecht
, J. Appl. Phys.
46
, 250
(1975
).7.
8.
M. K.
Weilmeier
, K. M.
Colbow
, T.
Tiedje
, T.
van Buuren
, and L.
Xu
, Can. J. Phys.
69
, 422
(1991
).9.
S. R.
Johnson
, C.
Lavoie
, T.
Tiedje
, and J. A.
Mackenzie
, J. Vac. Sci. Technol. B
11
, 1007
(1993
). The optical model presented in this reference underestimates the subgap absorption, because the Lambertian scattering assumed in modeling the diffuse reflectance overestimates the losses from trapping of light scattered from the textured back surface of the wafer.10.
S. R.
Johnson
, C.
Lavoie
, E.
Nodwell
, M. K.
Nissen
, T.
Tiedje
, and J. A.
Mackenzie
, J. Vac. Sci. Technol. B
12
, 1225
(1994
).11.
D. M. Kirillov and R. A. Powell, U.S. Patent No. 5,118,200 (1992).
12.
American Xtal Technology, Dublin, CA, 94568.
13.
Union Carbide Advanced Ceramics, P.O. Box 94924, Cleveland, OH 44101.
14.
15.
16.
17.
G. D.
Cody
, T.
Tiedje
, B.
Abeles
, B.
Brooks
, and Y.
Goldstein
, Phys. Rev. Lett.
47
, 1480
(1981
).18.
19.
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