By comparison of LEED intensity–voltage data on GaAs (110) surfaces prepared by cleaving and by chemical etch followed by sputter annealing, we find the surfaces to be essentially the same in atomic geometry within the limits of experimental error. However, we find that important distinctions can be made between (110) surfaces prepared by these two methods when Fermi-energy pinning and UPS data are considered. In this regard, we show that Fermi-energy pinning is a particularly sensitive indicator of the degree of surface perfection and that the UPS data gives valuable information about the degree of perfection achieved by the different surface preparation techniques used. As an example of this, we show differences in the spatial distribution of damage on sputter-annealed and heat-cleaned surfaces which are seen by UPS. The sputtered surface is extremely imperfect prior to annealing. Finally, we find no evidence for intrinsic filled surface states in the band gap on the (111) As surface when prepared by heat cleaning or sputter annealing.

The electrical behavior of GaAs and other Schottky barriers is known to be affected by the presence of an oxide layer, but little is known of the effect of the oxide composition on the electrical characteristics (i.e., I-V and C-V). In this study, the surfaces of GaAs and AlxGa1−xAs were prepared in H2O, H2O2, and NH4OH, and electrical measurements were made of these Schottky barriers. The surface composition of these samples was studied with Auger electron spectroscopy and compared to the electrical behavior of the Schottky barriers. The presence of measurable amounts of As oxides in the oxide layer resulted in soft I-V characteristics. However, samples with predominantly Ga2O3 oxide layers (i.e., small amounts of As oxides) were found to exhibit more nearly ideal Schottky-barrier behavior, with conduction ideality values from 1.2 to 1.4.

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