THEORETICAL INVESTIGATIONS OF AS OVERLAYERS ON INP(110) SURFACES

As adsorption and interaction with InP(110) is investigated by means o f total-energy minimization calculations. We find that the As-P exchan ged configuration has higher energy than the As/InP(110) epitaxially c ontinued layer structure (ECLS), for all types of As reservoirs consid ered. In the presence of an additional As layer in ECLS (i.e., 1.5 ML adsorbed As), however, the exchanged configuration is only slightly hi gher in energy than the nonexchanged one. We conclude that the As-P ex change process is energetically unfavorable, and should in any case no t be complete at room temperature, as suggested in a recent report. Ou r conclusion is supported by results of a photoemission study, includi ng As absorption, desorption, and redeposition, according to which the process is nonreversible. [S0163-1829(97)05947-X].