We propose a method for forming a top distributed Bragg reflector (DBR) during very-low temperature (VLT) molecular-beam epitaxy (MBE) growth that is independent of the substrate being used. By varying the arsenic overpressure during VLT MBE, it was determined by Auger electron spectroscopy and cross-section transmission electron microscopy that alternating layers of polycrystalline GaAs and amorphous (Al,As) can be deposited. Because these layers are not single crystal, they can be grown on any host lattice. After lateral wet oxidation, the polycrystalline GaAs does not undergo any significant changes; whereas the amorphous (Al,As) becomes an amorphous aluminum oxide. An index step of Δn = 1.88 is realized between these two layers which makes it possible to fabricate a high efficiency DBR with very few polycrystal-GaAs/amorphous-Al-oxide pairs on GaAs-, GaP-, or InP-based materials. Using reflectivity measurements, we demonstrate a five pair GaAs/AlAs-based DBR grown on an InP substrate that reflects wavelengths between 1.4 and 2.3 μm up to 95%. © 1999 American Institute of Physics.