相关论文: Extraction of absorption coefficients from GaN nan…
We analyze the strain state of GaN nanowire ensembles by x-ray diffraction. The nanowires are grown by molecular beam epitaxy on a Si(111) substrate in a self-organized manner. On a macroscopic scale, the nanowires are found to be free of…
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…
Self-assembled GaN nanowires are typically grown on Si substrates with convenient nucleation layers. Light-emitting devices based on arrays of GaN nanowires require that the nucleation layer is electrically conductive and optically…
Semiconductor nanowires are attractive for photovoltaic applications because light absorption can be enhanced compared to planar layers due to the more complex coupling of light with wavelength-scale matter. However, experimentally it is…
Top-down fabricated GaN nanowires, 250 nm in diameter and with various heights, have been used to experimentally determine the evolution of strain along the vertical direction of 1-dimensional objects. X-ray diffraction and…
AlN layers with thicknesses between 2 and 14 nm were grown on Si(111) substrates by molecular beam epitaxy. The effect of the AlN layer thickness on the morphology and nucleation time of spontaneously formed GaN nanowires (NWs) was…
Single GaN nanowires formed spontaneously on a given substrate represent nanoscopic single crystals free of any extended defects. However, due to the high area density of thus formed GaN nanowire ensembles, individual nanowires coalesce…
Gallium nitride nanowires were grown on c-plane, r-plane and m-plane sapphire substrates in a showerhead metalorganic chemical vapor deposition system using nickel catalyst with trimethylgallium and ammonia as precursors. We studied the…
We investigate the structural and optical properties of spontaneously formed GaN nanowires with different degrees of coalescence. This quantity is determined by an analysis of the cross-sectional area and perimeter of the nanowires obtained…
An impact of thin metallic ZrN layers on Si and sapphire wafers on substrate temperature during MBE growth of GaN nanowires is studied. Using nucleation kinetics of GaN as a sensitive probe we show that a thin ZrN layer strongly increases…
Manipulation of surface architecture of semiconducting nanowires with a control in surface polarity is one of the important objectives for nanowire based electronic and optoelectronic devices for commercialization. We report the growth of…
The present study elucidates the correlation between the structural and optical properties of GaN nanowires grown on Si(111) substrate by plasma assisted molecular beam epitaxy (PA-MBE) technique under various growth conditions. GaN NWs…
In molecular beam epitaxy, the spontaneous formation of GaN nanowires on Si(111) substrates at elevated temperatures is limited by the long incubation time that precedes nanowire nucleation. In this work, we present three unconventional…
Selective area growth of GaN nanostructures has been performed on full 2" c-sapphire substrates using Si3N4 mask patterned by nanoimprint lithography (array of 400 nm diameter circular holes). A new process has been developed to improve the…
The use of highly efficient and solarblind GaN photocathodes as part of multichannel plate UV detectors for applications in astronomy would strongly benefit from the direct growth of GaN on typical window materials with high transmission…
We report on simulations and measurements of the optical absorption of silicon nanowires (NWs) versus their diameter. We first address the simulation of the optical absorption based on two different theoretical methods : the first one,…
We investigate in detail the self-assembled nucleation and growth of GaN nanowires by molecular beam epitaxy on crystalline TiN films. We demonstrate that this type of substrate allows the growth of long and thin GaN nanowires that do not…
We have selectively grown thin epitaxial GaAs films on Ge substrates with the aid of a 200 nm thin SiO2 mask layer. The selectively grown structures have lateral sizes ranging from 1 um width up to large areas of 1 by 1 mm2. The growth is…
The absorption spectra of silicon nanowires (SiNW) are calculated using semi-empirical $sp^{3}d^{5}s^{*}$ tight binding (TB) and Density Functional Theory (DFT) methods. The role of diameter, wave function symmetry, strain and…
N-type doping of GaAs nanowires has proven to be difficult because the amphoteric character of silicon impurities is enhanced by the nanowire growth mechanism and growth conditions. The controllable growth of n-type GaAs nanowires with…