Properties of Homoepitaxial and Heteroepitaxial GaN Layers Grown by Plasma-Assisted MBE

✍ Scribed by Sánchez-García, M. A. ;Naranjo, F. B. ;Pau, J. L. ;Jiménez, A. ;Calleja, E. ;Muñoz, E. ;Molina, S. I. ;Sánchez, A. M. ;Pacheco, F. J. ;García, R.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 302 KB
• Volume: 176
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/(sici)1521-396x(199911)176:1<447::aid-pssa447>3.0.co;2-a

✦ Synopsis

This work presents a comparative study of the growth by plasma-assisted molecular beam epitaxy (MBE) of GaN layers on four different substrates: Si(111), Al 2 O 3 (0001), GaN/Al 2 O 3 and ELOG GaN/Al 2 O 3 templates. Optimization of the growth parameters for the case of growth of GaN layers on silicon substrates leads to smooth films with surface roughness below 5 nm, intense low temperature photoluminescence (PL) (15 meV FWHM) and X-ray diffraction (XRD) values of 8.5 arcmin. (FWHM). The quality of the material clearly improves when growing on sapphire substrates obtaining intense low-and-room temperature PL (10 and 54 meV FWHM, respectively) and XRD values of 6.5 arcmin (FWHM). The best GaN epilayers (intense low-temperature PL emissions with FWHM of 4 meV) are obtained when growing homoepitaxially on high quality GaN/Al 2 O 3 templates, reproducing the optical and structural properties of the template underneath. Finally, the dislocation density decreases drastically from (6 to 10) Â 10 9 cm 2 for the case of silicon substrate to <10 6 cm ± ±2 for the GaN layers grown on the ELOG templates.

Properties of Homo-and Heteroepitaxial GaN Layers