We report the molecular beam epitaxy (MBE) growth of lightly Mn-doped Zn-Sn-As-based compounds on (0 0 1) InP substrates. Our XRD measurements showed peaks assignable to sphalerite-type ZnSnAs2:Mn, a supposition further supported by our EPMA and TEM analyses. The optimum substrate temperature T-S resulting into the most stoichiometric ZnSnAs2 epitaxial films was first determined by growing undoped ZnSnAs2 at different T-S of 265, 280, 300, and 320 degrees C. The sample grown at T-S = 300 degrees C showed the best stoichiometry according to our EPMA composition studies. We then prepared lightly Mn-doped ZnSnAs2 at this optimum substrate temperature of 300 degrees C. Room temperature SQUID measurements revealed paramagnetic response with weak ferromagnetism as evident from the slightly S-shape M-H curve superimposed on a linearly increasing magnetization with increasing field. (c) 2007 Elsevier B.V. All rights reserved.