  Cubic InN films were grown on top of a c-GaN buffer layer by rf-plasma
assisted MBE at different growth temperatures. X-Ray diffraction investigations
show that the c-InN layers consist of a nearly phase-pure zinc blende (cubic)
structure with a small fraction of the wurtzite (hexagonal) phase grown on the
(111) facets of the cubic layer. The content of hexagonal inclusions is
decreasing with decreasing growth temperature. The full-width at half-maximum
(FWHM) of c-InN (002) rocking curve is about 50 arcmin. Low temperature
photoluminescence measurements reveal a band gap of about 0.61eV for cubic InN.
