Thin III-V nitride semiconductors fidms are commonly prepared using metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE). These methods often require high temperatures (800–1000°C) for the films to grow epitaxially. In the present work, we deposited AlxIn1-xN films on Si substrates by reactive magnetron sputttering method at low substrate temperature. The properties of the films have been studied by RBS, x-ray diffraction, and optical measurements. The AlxIn1-xN films deposited at room temperature were confirmed to be crystalline by x-ray diffraction. Band gap energies of our AlxIn1-xN alloys varies from 1.9 ev to 4.2 ev The bandgap energy vs. lattice constant curve was constructed and confirmed to bow downwards.