Epitaxial wurtzite aluminum nitride (AIN) and gallium nitride (GaN) films h
ave been grown on Si(1 1 1) by plasma-assisted molecular beam epitaxy (PA-M
BE). Two-dimensional growth (2DG) of single-crystalline AIN films is achiev
ed on Si(1 1 1) near stoichiometric supply of aluminum and atomic nitrogen.
Two distinct categories of AIN-surface reconstructions have been observed.
GaN films exhibit 1 x 1 high-energy electron diffraction (RHEED) pattern i
f grown between 650 degrees C and 770 degrees C substrate temperature on AI
N buffers. Stable Ga- and N-adlayer-induced surface reconstructions have be
en studied below 600 degrees C after the growth. The X-ray diffraction (XRD
) pattern show sharp and well separated (0 0 0 1) reflections of wurtzite G
aN and AIN indicating complete texture with GaN[0 0 0 1]parallel to AIN[0 0
0 1]parallel to Si[1 1 1 ]. From the determined GaN lattice constant compl
ete strain relaxation can be concluded which is further confirmed by the te
mperature-dependent photoluminescence (PL) investigations. (C) 1999 Elsevie
r Science B.V. All rights reserved.