Vertical GaN nanowires are grown in a self-induced way on a sputtered Ti film by plasma-assisted molecular beam epitaxy. Both in situ electron diffraction and ex situ ellipsometry show that Ti is converted to TiN upon exposure of the surface to the N plasma. In addition, the ellipsometric data demonstrate this TiN film to be metallic. The diffraction data evidence that the GaN nanowires have a strict epitaxial relationship to this film. Photoluminescence spectroscopy of the GaN nanowires shows excitonic transitions virtually identical in spectral position, line width, and decay time to those of state-of-the-art GaN nanowires grown on Si. Therefore, the crystalline quality of the GaN nanowires grown on metallic TiN and on Si is equivalent. The freedom to employ metallic substrates for the epitaxial growth of semiconductor nanowires in high structural quality may enable novel applications that benefit from the associated high thermal and electrical conductivity as well as optical reflectivity.
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http://dx.doi.org/10.1021/acs.nanolett.5b00251 | DOI Listing |
Natl Sci Rev
January 2025
Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China.
The noise equivalent temperature difference (NETD) indicates the minimum temperature difference resolvable by using an infrared detector. The lower the NETD, the better the sensor can register small temperature differences. In this work, we proposed a strategy to achieve a high temperature resolution using a superconducting nanowire single-photon detector (SNSPD) with ultra-high sensitivity.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Applied Physics and Integrated Education Institute for Frontier Science and Technology (BK21 Four), Kyung Hee University, Yongin 17104, Korea.
One-dimensional (1D) vertical nitrides are highly attractive for light-emitting diode (LED) applications because they are useful for overcoming the drawbacks of conventional GaN planar structures. However, the internal quantum efficiency (IQE) of GaN multi-quantum-well (MQW) nanowire (NW) LEDs, typical 1D GaN structures, is still too low to replace standard planar LEDs. Here, we report a phenomenon of light amplification from core-shell InGaN/GaN NW LEDs by incorporating graphene quantum dots (GQDs).
View Article and Find Full Text PDFNano Lett
January 2025
Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 0E9, Canada.
Semiconductor nanowires have become emerging photocatalysts in artificial photosynthesis processes for solar fuel production. For reduction reactions, semiconductor photocatalysts with high reducing powers are highly desirable, especially for chemicals that are extremely difficult to reduce. This study introduces a new semiconductor photocatalyst, scandium (Sc)-III-nitrides, which have higher reducing powers than all conventional semiconductor photocatalysts.
View Article and Find Full Text PDFNatl Sci Rev
January 2025
Division of Advanced Materials Engineering, College of Engineering, Research Center for Advanced Materials Development (RCAMD), Jeonbuk National University (JBNU), Jeonju 54896, South Korea.
Ever-increasing demand for efficient optoelectronic devices with a small-footprinted on-chip light emitting diode has driven their expansion in self-emissive displays, from micro-electronic displays to large video walls. InGaN nanowires, with features like high electron mobility, tunable emission wavelengths, durability under high current densities, compact size, self-emission, long lifespan, low-power consumption, fast response, and impressive brightness, are emerging as the choice of micro-light emitting diodes (µLEDs). However, challenges persist in achieving high crystal quality and lattice-matching heterostructures due to composition tuning and bandgap issues on substrates with differing crystal structures and high lattice mismatches.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Department of Physics, IQIM, California Institute of Technology, Pasadena, California 91125, USA.
External coherent fields can drive quantum materials into nonequilibrium states, revealing exotic properties that are unattainable under equilibrium conditions-an approach known as "Floquet engineering." While optical lasers have commonly been used as the driving fields, recent advancements have introduced nontraditional sources, such as coherent phonon drives. Building on this progress, we demonstrate that driving a metallic quantum nanowire with a coherent wave of terahertz phonons can induce an electronic steady state characterized by a persistent quantized current along the wire.
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