Figure 8 ,Table 1
    • Figure Fig. 1.  (Color online) (a) XRD spectra of Ga-assisted AlN films under varying TMGa flow rates respectively, (b) EDS spectra of Ga-assisted AlN sample S5.

    • Figure Fig. 2.  (Color online) (a)−(e) The cross-sectional SEM images of Ga-assisted AlN films grown under different TMGa flow rates and corresponding 5 × 5 μm2 AFM images, (f) Ga-assisted AlN growth rates as a function of Ga proportion.

    • Figure Fig. 3.  (a)−(f) SEM images of Ga-assisted AlN films grown with different Ga flow rates.

    • Figure Fig. 4.  (Color online) The results of the Raman spectroscopy measurement.

    • Figure Fig. 5.  SEM images of AlN nucleation morphology (a) without TMGa and (b) with 80% TMGa.

    • Figure Fig. 6.  (Color online) (a−c) Schematic diagram of Ga-assisted AlN growth, (d−f) W/O Ga-assisted AlN growth.

    • Figure Fig. 7.  (Color online) (a, b) X-ray rocking curves of AlN (002) and (102) planes of samples S1−S5, (c) the variation curves of the full width at FWHM of AlN (002) and (102) planes of samples S1−S5, (d) AlN growth rate and growth temperature as function of Ga proportion.

    • Figure Fig. 8.  (Color online) FWHM values of AlN (002) (a) and (102) (b) planes, surface morphology (c) and growth thickness (d) of Sample S6.