Novel selective area growth (SAG) method for regularly arranged AlGaN nanocolumns using nanotemplates

• Published in: Journal of crystal growth 2015-09, Vol.425, p.316-321
• Main Authors: Yamano, Koji, Kishino, Katsumi, Sekiguchi, Hiroto, Oto, Takao, Wakahara, Akihiro, Kawakami, Yoichi
• Format: Article
• Language: English
• Subjects: A1. Nanostructures; A3. Molecular beam epitaxy; Aluminum gallium nitrides; Arrays; B1. Nitrides; B2. Semiconducting III–V, materials; Band spectra; Gallium nitrides; Lattice parameters; Nanostructure; Wavelengths
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2015.02.051

We have demonstrated a novel selective area growth (SAG) method based on rf-plasma-assisted molecular beam epitaxy for AlGaN nanocolumns using nanotemplates. The nanotemplates, which were prepared on a metal-organic chemical vapor deposition-GaN template, consisted of a triangular lattice of nanopillars with a lattice constant from 200 to 400nm. For nanopillars with a lattice constant of 400nm, the gap width between adjacent pillars was varied from 30 to 130nm. The well-controlled SAG of GaN nanocolumns was achieved on nanopillar arrays with gap widths of less than approximately 45nm. The beam shadowing effect, which was induced in the high-density nanopillar arrays with small gaps, was a key mechanism in the SAG. This gap width condition for SAG was satisfied for lattice constants from 200 to 400nm. Using the nanotemplate SAG technology, the SAG of AlGaN nanocolumn arrays was achieved for Al compositions of 0.13, 0.22, 0.43, and 1. Single-peak photoluminescence (PL) spectra of AlGaN were observed, whose wavelengths were close to the calculated bandgap wavelengths using the bandgaps of AlN (6.015eV) and GaN (3.39eV) and a bowing parameter of 0.98eV. •We proposed a novel selective area growth (SAG) method based on rf-plasma-assisted molecular beam epitaxy for AlGaN nanocolumn using nanotemplates.•The nanotemplate consisted of a triangular lattice of nanopillars prepared on an MOCVD-GaN template.•Well-controlled GaN nanocolumns were grown by SAG on the nanopillar arrays with gap widths between adjacent pillars of less than approximately 60nm.•Using the nanotemplate SAG technology, the SAG of AlGaN nanocolumn arrays was achieved for Al compositions of 0.13, 0.36, 0.43, and 1.