The growth of InAs nanowires by molecular beam epitaxy only takes place in a narrow temperature range, independent of the method used to induce the growth: with (Au or Mn) or without metal catalysts. Our findings suggest that the physical chemistry of the intermetallic compound formed during the catalyzed growth of the NWs is not relevant for the induction of the growth. Moreover, the lattice structure of the wires always shows wurtzite sections. Our results indicate the need of a unified model for the metal-catalyzed and self-catalyzed growth of nanowires. (C) 2010 Elsevier B.V. All rights reserved.