We have fabricated stacked InAs quantum dots (QDs) on InP(3 1 1)B substrates. An ultra-high density of QDs was obtained by a method of compensation of strain by controlling the lattice constant of spacer layers without destruction of QDs size uniformity and ordering structure which is characteristic of QDs formation on (3 1 l)B surface. A strong 1.58 mum photoluminescence was observed in this sample at room temperature. (C) 2002 Elsevier Science B.V. All rights reserved.