High-Quality GaN on Si Substrate Using AlGaN/AlN Intermediate Layer

A single crystal GaN thin film was successfully grown on a Si(111) substrate by means of atmospheric-pressure metalorganic chemical vapor deposition. An intermediate layer consisting of AlN and AlGaN improved the quality of GaN on Si with a mirror-like surface and reduced the pits and cracks over the surface. The full width at half maximum (FWHM) of the double-crystal X-ray rocking curve for GaN(0004) was 600 arcsec. Photoluminescence measurement at 4.2 K for a nondoped film revealed a sharp band-edge emission with a FWHM of 8.8 meV, which is the narrowest value reported to date. GaInN multi-quantum-well structure was grown on this structure and showed a strong blue emission peaking at 470 nm. The results suggest GaN on Si with an AlGaN/AlN intermediate layer provides reliable light emitting devices on Si substrate.