Abstract
The present paper discusses the use of selective photoetching with H3PO4:H2O2 for characterizing various AIIIBV compounds and detecting misfit dislocations in transition layers. For GaP, the results obtained are compared with those realized with the use of an AB etchant for which suitable conditions for the structural etching of {001} material and the characterization of cleavage faces are given. The direction of the dislocation line is inferred from the shape and orientation of etch pits. The etch figures of different types of misfit dislocations are discussed.