Integration of GaN Crystals on Micropatterned Si(0 0 1) Substrates by Plasma-Assisted Molecular Beam Epitaxy

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• 作者：Fabio Isa ; Caroline Ch猫ze ; Marcin Siekacz ; Christian Hauswald ; Jonas L盲hnemann ; Sergio Fern谩ndez-Garrido ; Thomas Kreiliger ; Manfred Ramsteiner ; Yadira Arroyo Rojas Dasilva ; Oliver Brandt ; Giovanni Isella ; Rolf Erni ; Raffaella Calarco ; Henning Riechert ; Leo Miglio
• 刊名：Crystal Growth & Design
• 出版年：2015
• 出版时间：October 7, 2015
• 年：2015
• 卷：15
• 期：10
• 页码：4886-4892
• 全文大小：461K
• ISSN：1528-7505

文摘

We present an innovative approach to integrate arrays of isolated, strain-free GaN crystals on patterned Si substrates. First, micrometer-sized pillars are patterned onto Si(0 0 1) substrates. Subsequently, 2.5 渭m Si substrates are deposited by low-energy plasma-enhanced chemical vapor deposition, forming crystals mostly bounded by {1 1 1}, {1 1 3}, and {15 3 23} facets. Plasma-assisted molecular beam epitaxy is then used for GaN deposition. GaN crystals with slanted {0 0 0 1} facets having a root-mean-square surface roughness of 0.7 nm are obtained for a deposited material thickness of >3 渭m. Microphotoluminescence measurements performed at room and cryogenic temperature show no yellow luminescence and a neutral donor-bound A exciton transition at 3.471 eV (10 K) with a full width at half-maximum of 10 meV. Microphotoluminescence and micro-Raman spectra reveal that GaN grown on Si pillars is strain-free. Our results indicate that the shape of GaN crystals can be tuned by the pattern periodicity and that a reduction of threading dislocations is achieved in their top part.