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We report here the first results of our study of metal/III–V semiconductor contacts :Ag–GaAs (001) and Ag–InP (001). Clean GaAs (001) and InP (001) surfaces, under various conditions of stoichiometry, are obtained by ion etching followed by annealing and arsenic or phosphorous adsorption and carefully characterized by AES, LEED, and ELS. Using these techniques some correlations between surface stoichiometry, surface structures, and electronic surface states have been found. On these surfaces the metallization has been carried out by an MBE-like technique. The results obtained show that the Schottky barrier height changes according to the conditions of surface preparation. To explain these results, different hypotheses are discussed.

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A new method of Ar ion beam etching of InP using a LN2 cooled sample holder is described. Smooth and low-damage etched surfaces have been obtained using this technique. Auger electron spectroscopy measurements and laser Raman spectroscopy analysis indicated that the morphology degradation was significantly reduced.

For the first time, we report contact potential difference (CPD) measurements, using the Kelvin vibrating condensor method, on GaAs (001) layers in situ grown by molecular beam epitaxy (MBE). By using a tungsten rod [calibrated with a W(110) crystal] as reference, absolute determinations of the work function have been done on several surface structures. The MBE layers used for this study were n-type tin-doped 5×1016 cm−3 (μ300K∠4500 cm−2 V−1s−1) and p-type undoped 5×1014 cm−3 (μ300K∠380 cm−2 V−1  s−1) layers. For more than 20 layers tested, no significant work function differences were found between n-type and p-type layers of the same surface structure [c (4×4), c (2×8), (1×6). etc.]. However, important work function differences were observed between the different surface structures. The first result is interpreted as a Fermi level pinning by a high density surface state band (≳1012 cm−2) and compares with recent theoretical and experimental investigations, whereas possible changes in electron affinity due to surface dipole variation with the surface reconstruction are taken into account in the discussion of the second result.