Controllable cubic and hexagonal GaN growth on GaAs(001) substrates by molecular beam epitaxy

Two kinds of GaN samples were grown on GaAs(0 0 1) substrates. One is grown on nitridized GaAs surface, the other is grown on nitridized AlAs buffer G aAs substrate. X-ray diffraction and photoluminescence measurements find th at the GaN sample directly grown on GaAs substrate is pure cubic phase and those grown on AlAs buffer is pure hexagonal phase. The present study shows that the phase of GaN samples grown on GaAs substrates can be controlled u sing different buffer layers. (C) 2000 Elsevier Science B.V. All rights res erved.