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The transport of holes through p-doped wurtzite bulk GaN and AlGaN is poor so transport of holes through GaN/AlGaN superlattices has been proposed and investigated theoretically and experimentally with experimental results showing poor…

Applied Physics · Physics 2023-09-19 Mengxun Bai , Judy Rorison

Silicon (Si) is the primary donor dopant in gallium nitride (GaN), introduced through epitaxial growth or ion implantation. However, precise control over Si diffusion remains a critical challenge for high-performance device applications.…

Thanks to its high refractive index contrast, band gap and polarization mismatch compared to GaN, In0.17Al0.83N layers lattice-matched to GaN are an attractive solution for applications such as distributed Bragg reflectors, ultraviolet…

Van der Waals assembly enables exquisite design of electronic states in two-dimensional (2D) materials, often by superimposing a long-wavelength periodic potential on a crystal lattice using moir\'e superlattices. Here we show that…

Deterministic and bright quantum light sources based on scalable semiconductor technologies are a crucial building block for future quantum communication networks. While circular Bragg gratings (CBGs) are highly effective for extracting…

We report on the fabrication of pseudomorphic wurtzite GaMnN grown on GaN with Mn concentrations up to 10% using molecular beam epitaxy. According to Rutherford backscattering the Mn ions are mainly at the Ga-substitutional positions, and…

Reflected neutron beam originating from a crystal monochromator contains higher order wavelength contribution. Creating multilayer mirror structures with custom reflectivity curves including a monochromatic polarized neutron beam is a…

Materials Science · Physics 2011-09-23 D. G. Merkel , L. Bottyán , B. Nagy , Sz. Sajti , E. Szilágyi , R. Kovács-Mezei

We investigate the diffraction conditions and associated formation of stopgaps for waves in crystals with different Bravais lattices. We identify a prominent stopgap in high-symmetry directions that occurs at a frequency below the…

Since graphene was synthesized the interest for building new 2D and 3D structures based on the carbon allotropes has been growing every day. One of these 3D structures is know as carbon schwarzites. Schwarzites consist of carbon…

Materials Science · Physics 2020-08-26 Raphael M. Tromer , Levi C. Felix , Cristiano F. Woellner , Douglas S. Galvao

We report the fabrication and characterization of photonic waveguides from sputtered aluminum nitride (AlN). The AlN films were deposited on 6" silicon substrates with a 3 $\mu$m buried silicon oxide layer using reactive DC magnetron…

The MBE-grown GaAs/AlGaAs superlattice with Si-doped barriers has been used to study a 3D-2D transition under the influence of the in-plane component of applied magnetic field. The longitudinal magnetoresistance data measured in tilted…

Mesoscale and Nanoscale Physics · Physics 2007-07-25 L. Smrčka , P. Vašek , P. Svoboda , N. A. Goncharuk , O. Pacherová , Yu. Krupko , Y. Sheikin

GaN-nanorods grown on Si(111) substrates are found strain- and defect-free as characterized by micro Raman spectroscopy, secondary electron (SE) and cathode-luminescence (CL) imaging. The matrix supporting the nanorods bears the brunt of…

Materials Science · Physics 2007-05-23 H. W. Seo , Q. Y. Chen , M. N. Iliev , W. K. Chu , L. W. Tu , C. L. Hsiao , James K. Meen

The wurtzite structure is one of the most frequently found crystal structures in modern semiconductors and its inherent spontaneous polarization is a defining materials property. Despite this significance, confusion has been rampant in the…

Materials Science · Physics 2025-05-07 Simon Fichtner , Mohamed Yassine , Chris van de Walle , Oliver Ambacher

One of the ways to use graphene in field effect transistors is to introduce a band gap by quantum confinement effect [1]. That is why narrow graphene nanoribbons (GNRs) with width less than 50nm are considered to be essential components in…

The reflectivity of various Bragg reflectors in connection to waveguide structures, including nanowires, has been investigated using modal reflection and transmission matrices. A semi-analytical model was applied yielding increased…

Optics · Physics 2012-06-25 Guro Kristin Svendsen , Helge Weman , Johannes Skaar

The nature of the cubic-like state in the lead-free piezoelectric ceramics 0.5K0.5Na0.5NbO3-0.5Na0.5Bi0.5TiO3 (KNN-50BNT) has been examined in detail by synchrotron x-ray diffraction (SD), selected area electron diffraction (SAED), neutron…

Silicon is the most popular material used in electronic devices. However, its poor optical properties owing to its indirect band gap nature limit its usage in optoelectronic devices. Here we present the discovery of super-stable…

Materials Science · Physics 2015-04-17 Young Jun Oh , In-Ho Lee , Sunghyun Kim , Jooyoung Lee , K. J. Chang

The structure of an Al(111)3x3-Si surface was examined by combining data from positron diffraction and core-level photoemission spectroscopy. Analysis of the diffraction rocking curves indicated that the overlayer had a flat honeycomb…

InGaN light-emitting diodes (LEDs) are more efficient and cost effective than incandescent and fluorescent lighting, but lattice mismatch limits the thickness of InGaN layers that can be grown on GaN without performance-degrading…

Applied Physics · Physics 2019-08-05 Kevin P. Greenman , Logan Williams , Emmanouil Kioupakis

The understanding of strongly-correlated materials, and in particular unconventional superconductors, has puzzled physicists for decades. Such difficulties have stimulated new research paradigms, such as ultra-cold atom lattices for…

Mesoscale and Nanoscale Physics · Physics 2018-05-22 Yuan Cao , Valla Fatemi , Shiang Fang , Kenji Watanabe , Takashi Taniguchi , Efthimios Kaxiras , Pablo Jarillo-Herrero