Statistical Analysis of Local Composition and Luminescence in InGaN Grown by Molecular Beam Epitaxy
Tóm tắt
InGaN layers grown by molecular beam epitaxy are investigated in terms of their compositional homogeneity using transmission electron microscopy and cathodoluminescence spectroscopy performed with high spatial resolution. Strong fluctuations of the indium content were found in bulk-like layers, which could be partially reduced by modulating the indium flux during growth, i. e. by nominally growing a short period GaN/InGaN superlattice. For indium compositions above x ≠ 0.1 this approach fails. Strained InGaN in quantum wells exhibits lateral fluctuations on an atomic scale and on a scale of several hundred nanometers. The results are discussed in view of the origin of inhomogeneous indium incorporation.
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