We report here the first results of our study of metal/III–Vsemiconductor 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.