Epitaxial layers were grown onto bulk GaN crystals, by means of metalorganic vapor phase epitaxy, and were studied using X-ray diffraction and optical photoluminescence techniques. It was found that most of the layers had smaller lattice constants than those of the substrates; thus indicating a lower concentration of point defects.

H.Teisseyre, M.Leszczynski, T.Suski, I.Grzegory, M.Bockowski, J.Jun, S.Porowski, K.Pakula, J.L.Robert, B.Beaumont, P.Gibart, M.Vaille, J.P.Faurie: Semiconductor Science and Technology, 1997, 12[2], 240-3