Figures

Figure 1a

AFM (5x5µm2) scan showing the layer morphology for 180 sec SiN treatment time. The GaN islands density is about 1x109 cm-2.

Figure 1b

AFM (5x5µm2) scan showing the layer morphology for 300 sec SiN treatment time. The GaN islands density is about 5x108 cm-2.

Figure 1c

AFM (5x5µm2) scan showing the layer morphology for 480 sec SiN treatment time. The GaN islands density is about 3x108 cm-2.

Figure 1d

AFM (5x5µm2) scan showing the layer morphology for 720 sec SiN treatment time. The GaN islands density is about 1x108 cm-2.

Figure 2

Comparison between reflectivity spectra recorded during the growth of GaN/sapphire standard epilayer and Ultra Low dislocation (ULD) GaN/sapphire. Arrows indicate where the growth starts.

Figure 3

High Resolution image of the interface in a ULD GaN/sapphire sample.

Figure 4

Cross-sectional bright field image of the ULD GaN/sapphire sample showing the interface region. The arrow indicates the SiN coverage.

Figure 5

Near band gap low temperature photoluninescence of ULD GaN/sapphire

Figure 6

Decays of the free-excitons and I2 PL intensities recorded at 13K

© 2002 The Materials Research Society