The Zn/Se flux ratio employed during the early stages of molecular beam epitaxy of pseudomorphic ZnSe/GaAs(001) as well as lattice-matched ZnSe/In0.04Ga0.96As(001) heterostructures controls the density of the native stacking faults, which have been associated with the early degradation of blue-green lasers. In particular, the density of Shockley stacking fault pairs decreases by three to four orders of magnitude and that of Frank stacking faults by one order of magnitude in going from Zn-rich to Se-rich interfaces. (C) 1997 American Institute of Physics.