Growth by molecular beam epitaxy of MnSb on InP(001) has been studied over a range of substrate temperatures (250-425 degrees C) and Sb:Mn flux ratios (2:1 to 8:1). Two growth phases were observed, their predominance mainly dependent on substrate temperature. These have been identified as MnSb (found preferentially at low temperatures) and InSb (found preferentially at high temperatures). The latter phase forms due to In out-diffusion from the substrate, leading to a granular film with increased total thickness and a very rough buried interface. This reaction only occurs in the presence of both Mn and Sb incident fluxes: when exposed to an Sb flux alone, very small islands of InSb are formed at the surface of InP due to residual In clusters but no disruption of the substrate occurs. No such effect was observed for growth on GaAs (001) and (111)B. Implications for the growth of hybrid epitaxial systems for semiconductor spintronics are discussed. (c) 2006 Elsevier B.V. All rights reserved.