Optical Studies of the Interface States at GaAs-Metal Schottky Barrier Junctions.
Final rept. 1 Oct 75-29 Sep 78,
MISSOURI UNIV-ROLLA DEPT OF PHYSICS
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The goal of the proposed research was to study surface states at GaAs metal Schottky barrier junctions and the effects of oxygen exposure on the surface states using both optical and electrical measurements with the goal of correlating the optical and electrical results. The correlation could not be achieved because the optical measurements were unsuccessful in detecting the surface states. From the electrical measurements, the following results were obtained oxygen-exposure before the metallization with Al produces a large increase in the surface density of states peaking about 0.28 eV above the Fermi level Al-GaAs diodes metallized without oxygen exposure had ideality factors of n equal to less than 1.1 Ag-GaAs diodes with oxygen exposure also show a surface state density peaking about 0.3 eV above the Fermi level. However, the surface state density is considerably lower than for oxygen-exposed AlGaAs diodes Au-GaAs diodes with oxygen exposure show a surface state density which peaks about 0.45 eV above the Fermi level. Again, this density is considerably lower from the above, oxygen at a GaAs-metal interface plays an important role in determining the surface state density. The theoretical part of this study to calculate electronic energies at GaAs surface was also unsuccessful. Author
- Solid State Physics