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We investigated the suitability of aluminum nitride (AlN) for surface passivation and protection of gallium arsenide (GaAs), using a low-temperature passivation method. By varying the plasma power (100, 200 W) during etching, we found that 200 W produced better passivation. Using X-ray photoelectron spectroscopy, we quantitatively demonstrate that etching the GaAs at 200 W almost removed the GaAs oxide layer. To further study the surface passivation of GaAs, we deposited an AlN film by plasma-enhanced atomic layer deposition using trimethylaluminum and ammonia precursors at 250 °C. AlN passivation did not effectively smooth the GaAs surface, but did increase its photoluminescence intensity. This study shows that AlN coating by plasma-enhanced atomic layer deposition is a promising low-temperature method for GaAs surface passivation. [ABSTRACT FROM AUTHOR]

Surface passivation is an effective way to eliminate the surface states and to improve the optical properties of GaAs. Moreover, carriers restriction of wide bandgap materials also is a path to enhance photoluminescence. In this paper, Be-doped GaAs epilayer was growth on GaAs substrate by molecular beam epitaxy. The MgO films were deposited by atom layer deposition. It was used as not only passivation layer to eliminate surface states, but also barrier layer to restrict carriers. The carriers restriction was confirmed by photoluminescence and current-voltage characteristics of metal-insulator-semiconductor structure. As the result, the photoluminescence intensity of Be-doped GaAs with 5 nm MgO was 2.5 times higher than the bare Be-doped GaAs. [ABSTRACT FROM AUTHOR]