Photocorrosion of n-GaAs and passivation by Na{sub 2}S: A comparison of the (100), (110), and (111)B faces
- Univ. of Oregon, Eugene, OR (United States)
Photocorrosion of n-GaAs and passivation by Na{sub 2}S have been studied in a working photoelectrochemical cell as a function of crystal face orientation. Time-resolved photoluminescence studies of the (100), (110), and (111)B faces of n-GaAs show that Na{sub 2}S provides a similar degree of corrosion protection to the (100) and (110) faces, although the corrosion-induced surface states eventually formed at each interface are separated in energy by nearly 300 meV. Unlike (100) and (110), the (111)B surface is not passivated by Na{sub 2}. The high density of intrinsic surface states at the (111)B n-GaAs surface, and the lack of removal of these states by Na{sub 2}S, pins the Fermi level and prevents trap saturation. X-ray photoelectron spectroscopic studies of the three surfaces before and after Na{sub 2}S treatment show a significant degree of arsenic sulfide bonding on (100) and (110). The (111)B face shows very little As-S bonding, indicating that formation of interfacial sulfides plays an important role in the reduction of interfacial traps and passivation of the photocorrosion reaction. 44 refs., 11 figs., 3 tabs.
- DOE Contract Number:
- FG06-86ER45273
- OSTI ID:
- 535441
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Vol. 101, Issue 14; Other Information: PBD: 3 Apr 1997
- Country of Publication:
- United States
- Language:
- English
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