Premium
Al 1− x In x N/GaN bilayers: Structure, morphology, and optical properties
Author(s) -
Lorenz K.,
Magalhães S.,
Franco N.,
Barradas N. P.,
Darakchieva V.,
Alves E.,
Pereira S.,
Correia M. R.,
Munnik F.,
Martin R. W.,
O'Donnell K. P.,
Watson I. M.
Publication year - 2010
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200983656
Subject(s) - materials science , elastic recoil detection , metalorganic vapour phase epitaxy , rutherford backscattering spectrometry , analytical chemistry (journal) , chemical vapor deposition , relaxation (psychology) , surface roughness , lattice constant , thin film , optics , composite material , optoelectronics , epitaxy , diffraction , nanotechnology , chemistry , layer (electronics) , psychology , social psychology , physics , chromatography
Abstract High quality Al 1− x In x N/GaN bilayers, grown by metal organic chemical vapor deposition (MOCVD), were characterized using structural and optical techniques. Compositional analysis was performed using Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). The InN molar fraction x decreased approximately linearly with increasing growth temperature and ranged from x = 0.13 to 0.24. Up to x = 0.20 the layers grow pseudomorphically to GaN with good crystalline quality. These layers show a smooth surface with V‐shaped pits. Two layers with InN contents around 24% showed partial strain relaxation. However, the mechanisms leading to relaxation of compressive strain are very different in the two samples grown both at similar temperature but with different growth rates. One sample shows a decreased c/a ratio, as expected for relaxation of the compressive strain, while In was shown to be homogeneously distributed with depth. The other sample started to grow with x = 0.24 but relaxed mainly by reduction of the incorporated InN content towards the lattice‐match composition of x ∼ 0.17. Both samples have an increased surface roughness. All samples show strong Al 1− x In x N band edge luminescence with large bowing parameter and Stokes' shifts.