The microindentation studies have been reported for undoped and doped InAs/InP semiconductor alloys grown by metal organic vapor phase epitaxy (MOVPE). It was found that the microhardness value increases with increase of applied load and attains a constant value for further increase in the load. The mechanical properties like, fracture toughness, brittleness index, fracture surface energy and indentation size effect coefficient were determined using the microhardness value. The indented samples were etched in H2SO4:H2O2:H2O of the ratio of (1:1:1) for 30 s. This reveals the dislocation rosette patterns generated around the edges of the indentation on subsequent etching process. (c) 2006 Elsevier B.V. All rights reserved.