Curved-Lattice Epitaxial Growth of InxAl1–xN Nanospirals with Tailored Chirality

Hsiao, Ching‐Lien; Magnusson, Roger; Pališaitis, Justinas; Sandström, Per-Erik; Persson, Per O. Å.; Valyukh, Sergiy; Hultman, Lars; Järrendahl, Kenneth; Birch, Jens

doi:10.1021/nl503564k

Cited by 25 publications

(35 citation statements)

References 45 publications

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“…Successful growth of high quality epitaxial GaN continuous films on sapphire substrates [14], core-shell In x Al 1 À x N nanorods [15,16], and In x Al 1 À x N nanospirals [17] have recently been demonstrated by DC-MSE. In DC-MSE, growth conditions are as pure as in the case of MBE, which means utilizing an ultra-high vacuum (UHV) base pressure and ultra-high purity gases during the growth.…”

Section: Introductionmentioning

confidence: 99%

Liquid-target reactive magnetron sputter epitaxy of High quality GaN(0001̄) nanorods on Si(111)

Junaid

Chen

Pališaitis

et al. 2015

Materials Science in Semiconductor Processing

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Section: Introductionmentioning

confidence: 99%

Liquid-target reactive magnetron sputter epitaxy of High quality GaN(0001̄) nanorods on Si(111)

Junaid

Chen

Pališaitis

et al. 2015

Materials Science in Semiconductor Processing

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“…In order to avoid inhomogeneous films the substrate can be continuously rotated. Substrate rotation can also be used to grow exotic nanostructures, for example, chiral nanospirals [72].…”

Section: Sputtering Multiple Materialsmentioning

confidence: 99%

Piezoelectricity, Phase Stability, and Surface Diffusion in Multicomponent Nitrides

Tholander

2016

Linköping Studies in Science and Technology. Dissertations

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The cover image is a compilation inspired by key results from my research.During the course of research underlying this thesis, Christopher Tholander was enrolled in Agora Materiae, a multidiciplinary doctoral program at Linköping University, Sweden.c Christopher Printed by LiU-Tryck 2016 Till min familj AbstractThe last hundred years have been full of scientific discoveries leading to technological advances, such as, computers, smart phones, etc. Most of the advances would not have been possible without new discoveries within the vast field of materials science. The specific area within materials science covered in this thesis is multicomponent nitride alloys, which are commonly used as thin films in industrial applications, e.g., as hard wear-resistant coatings for cutting-tools or as part of intricate electronic components in mobile telecommunication devices. The core of this thesis is towards the fundamental understanding of existing, and the discovery of new, nitride alloys using theoretical tools. Knowledge about the quantum mechanics of the alloys was gained using density functional theory (DFT), alloy theory, and thermodynamics investigating piezoelectricity, phase stability, and surface diffusion.The focus of the piezoelectricity research is on piezoelectric properties of both ordered and disordered nitrides. The exploration of disordered wurtzite nitrides revealed important aspects of the nitride alloying physics and the implications for their piezoelectric response, in addition to the discovery of interesting alloy candidates and their synthesis, e.g., Y x In 1−x N. For the ordered nitrides, novel TMZnN 2 (TM = Ti, Zr, Hf) structures with high piezoelectric responses have been predicted as stable.The thermodynamic stability of novel alloys with interesting properties is investigated in order to determine if equilibrium or non-equilibrium synthesis is feasible. The studies consist of ternary phase diagrams of TM-Zn-N, mixing enthalpies for disordered Y x Al 1−x N and Y x In 1−x N that can be used to predict possible synthesis routes and guide experiments. In addition, mixing enthalpies for strained Sc x Al 1−x N/In y Al 1−y N superlattices show that the stability of certain phases and, therefore, the crystalline quality can be improved by modifying in-plane lattice parameters through higher indium content in the InAlN layers.Surface diffusion is studied because it is an important factor during thin film growth with, for example, physical vapor deposition (PVD). It is the main atomic v vi transport mechanism and, thus, governs the structure development of thin films. Specifically, the research is focused on diffusion on the surfaces of disordered alloys, and in particular Ti, Al, and N adatom diffusion on TiN and TiAlN surfaces. The investigations revealed that Ti adatom mobilities are dramatically reduced in the presence of Al in the surface layer on the TiN and Ti 0.5 Al 0.5 N(0 0 1) surfaces, while Al adatoms are largely unaffected. Furthermore, the reverse effect is found on the TiN (1 1 1) surf...

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“…The method of fabrication (briey described below, and in more detail elsewhere 12 ) allows for a high degree of control of the structural properties and tunability of the band gap.…”

Section: 11mentioning

confidence: 99%

In_xAl_1-xN chiral nanorods mimicking the polarization features of scarab beetles

et al. 2015

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The scarab beetle Cetonia aurata is known to reect light with brilliant colors and a high degree of circular polarization. Both color and polarization eects originate from the beetles exoskeleton and have been attributed to a Bragg reection of the incident light due to a twisted laminar structure. Our strategy for mimicking the optical properties of the Cetonia aurata was therefore to design and fabricate transparent, chiral lms. A series of lms with tailored transparent structures of helicoidal In x Al 1−x N nanorods were grown on sapphire substrates using UHV magnetron sputtering. The value of x is tailored to gradually decrease from one side to the other in each nanorod normal to its growth direction. This introduces an in-plane anisotropy with dierent refractive indices in the direction of the gradient and perpendicular to it. By rotating the sample during lm growth the in-plane optical axis will be rotated from bottom to top and thereby creating a chiral lm. Based on Muellermatrix ellipsometry, optical modeling has been done suggesting that both the exoskeleton of Cetonia aurata and our articial material can be modeled by an anisotropic lm made up of a stack of thin layers, each one with its in-plane optical axis slightly rotated with respect to the previous layer. Simulations based on the optical modeling were used to investigate how pitch and thickness of the lm together with the optical properties of the constitutive materials aects the width and spectral position of the Bragg reection band.

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Curved-Lattice Epitaxial Growth of In_xAl_1–xN Nanospirals with Tailored Chirality

Cited by 25 publications

References 45 publications

Liquid-target reactive magnetron sputter epitaxy of High quality GaN(0001̄) nanorods on Si(111)

Liquid-target reactive magnetron sputter epitaxy of High quality GaN(0001̄) nanorods on Si(111)

Piezoelectricity, Phase Stability, and Surface Diffusion in Multicomponent Nitrides

In_xAl_1-xN chiral nanorods mimicking the polarization features of scarab beetles

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Curved-Lattice Epitaxial Growth of InxAl1–xN Nanospirals with Tailored Chirality

Cited by 25 publications

References 45 publications

Liquid-target reactive magnetron sputter epitaxy of High quality GaN(0001̄) nanorods on Si(111)

Liquid-target reactive magnetron sputter epitaxy of High quality GaN(0001̄) nanorods on Si(111)

Piezoelectricity, Phase Stability, and Surface Diffusion in Multicomponent Nitrides

InxAl1-xN chiral nanorods mimicking the polarization features of scarab beetles

Contact Info

Product

Resources

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Curved-Lattice Epitaxial Growth of In_xAl_1–xN Nanospirals with Tailored Chirality

In_xAl_1-xN chiral nanorods mimicking the polarization features of scarab beetles