Growth of high-quality GaN on Si(111) substrate by ultrahigh vacuum chemical vapor deposition

An ultrahigh vacuum chemical vapor deposition (UHVCVD) system was employed to grow high-quality GaN on a Si (111) substrate using a thin AlN buffer layer. X-ray diffraction, high-resolution electron microscopy (HREM), and photoluminescence (PL) data indicate that a single crystalline GaN layer with a wurtzite structure was epitaxially grown on a silicon substrate. The full width at half maximum (FWHM) of the x-ray rocking curve for the GaN (0002) diffraction was 16.7 arc min. A cross-sectional HREM image showed an amorphous SiN_x layer at the Si/AlN interface, as well as stacking faults and inversion domain boundaries in the GaN epilayer. An intense PL emission line, which is associated with the recombination of the donor bound exciton, was observed at 10 K PL spectra (FWHM=6.8 meV) and a strong band edge emission was obtained (FWHM=33 meV) as well, even at room temperature. These results indicate that high-quality GaN can be grown on Si (111) substrates using a UHVCVD growth method.