Picosecond photoluminescence studies of photocorrosion and passivation of n-GaAs in Na{sub 2}S-containing solutions
- Univ. of Oregon, Eugene, OR (United States)
Passivation of n-GaAs by Na{sub 2}S in an electrochemical cell has been studied using photoluminescence decays and voltage dependence of photoluminescence intensity. A significant increase in the degree of passivation of the (100) n-GaAs surface is seen when the concentration of Na{sub 2}S is increased above approximately1 M. The observed passivation in higher concentrations of Na{sub 2}S eventually deteriorates with extended exposure to light. The corrosion that develops when the n-GaAs is in higher concentrations of Na{sub 2}S leads to traps that can be occupied at all voltages. This behavior is different from corrosion seen in lower concentrations of Na{sub 2}S in which the traps can only be occupied at voltages greater than V = 0.0 V. Decay measurements at flatband potential and at open circuit indicate no significant changes in surface-trapping velocity as the Na{sub 2}S concentration is changed from 0.008 to 1 M. This suggests that repinning or removal of surface traps is not responsible for the passivation that is observed upon increasing the Na{sub 2}S concentration. An increase in the rate of charge transfer across the interface as the Na{sub 2}S concentration in the electrolyte is increased appears responsible. 24 refs., 7 figs., 3 tabs.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG06-86ER45273
- OSTI ID:
- 35458
- Journal Information:
- Journal of Physical Chemistry, Vol. 99, Issue 12; Other Information: PBD: 23 Mar 1995
- Country of Publication:
- United States
- Language:
- English
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