Gallium nitride is grown by plasma-assisted molecular-beam epitaxy on (111) and (001) silicon substrates using hafnium nitride buffer layers. Wurtzite GaN epitaxial layers are obtained on both the (111) and (001) HfN/Si surfaces, with crack-free thickness up to 1.2 Om. However, growth on the (001) surface results in nearly stress-free films, suggesting that much thicker crack-free layers could be obtained.
 This invention was made with government support under Grant (Contract) No. DE-AC03-76F00098 awarded by The United States Department of Energy to The Regents of the University of California. The government has certain rights to this invention.