AlGaN Nanocolumns Grown by Molecular Beam Epitaxy: Optical and Structural Characterization

✍ Scribed by Risti?, J. ;S�nchez-Garc�a, M.A. ;Calleja, E. ;Sanchez-P�ramo, J. ;Calleja, J.M. ;Jahn, U. ;Ploog, K.H.

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 319 KB
• Volume: 192
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/1521-396x(200207)192:1<60::aid-pssa60>3.0.co;2-o

✦ Synopsis

High quality AlGaN nanocolumns have been grown by molecular beam epitaxy on Si(111) substrates. Scanning Electron Microscopy micrographs show hexagonal, single crystal columns with diameters in the range of 30 to 60 nm. The nominal Al content of the nanocolumns was changed from 16% to 40% by selecting the flux ratio between the Al and the total III-element, while keeping the growth temperature and the active nitrogen constant. The nominal values of the Al content are consistently lower than the experimental ones, most likely due to the high Ga desorption rates at the growth temperature. The Al composition trend versus the Al flux is consistent with the E 2 phonon energy values measured by inelastic light scattering. These results open the possibility to grow high quality low dimensional structures based on AlGaN/GaN/AlGaN heterocolumns for basic studies and device applications.