0000000000598091
AUTHOR
Eleonora Secco
Structural characterization of selective area growth GaN nanowires by non-destructive optical and electrical techniques
The growth selectivity and structural quality of GaN nanowires obtained by plasma-assisted molecular beam epitaxy on pre-patterned GaN(0001) templates are investigated by means of non-destructive techniques. Optimum control over the nanowire arrangement and size requires a pitch between the mask apertures below twice the diffusion length of Ga atoms. Lower pitches, however, seem to slightly diminish the structural quality of the material, as revealed by the increase of the Raman peak linewidths. The photoluminescence spectra of the nanowires show a considerable presence of basal plane stacking faults, whose density increases for decreasing nanowire diameter. The capabilities of Kelvin probe…
Elemental distribution and structural characterization of GaN/InGaN core-shell single nanowires by Hard X-ray synchrotron nanoprobes
Improvements in the spatial resolution of synchrotron-based X-ray probes have reached the nano-scale and they, nowadays, constitute a powerful platform for the study of semiconductor nanostructures and nanodevices that provides high sensitivity without destroying the material. Three complementary hard X-ray synchrotron techniques at the nanoscale have been applied to the study of individual nanowires (NWs) containing non-polar GaN/InGaN multi-quantum-wells. The trace elemental sensitivity of X-ray fluorescence allows one to determine the In concentration of the quantum wells and their inhomogeneities along the NW. It is also possible to rule out any contamination from the gold nanoparticle …
Characterisation of single semiconductor nanowires by non-destructive spectroscopies
Los nanohilos semiconductores (NWs, de su nombre inglés, nanowires) tienen una amplia gama de aplicaciones en el campo de la optoelectrónica (emisores de luz y diodos láser), nano-electrónica (circuitos lógicos y transistores de efecto de campo), y detección y producción de energía (células solares). En términos generales, los NWs pueden ser descritos como nanoestructuras de forma alargada con diámetros que van típicamente de decenas a cientos de nanómetros, y con longitudes que oscilan desde pocas hasta las decenas de micras. Dicha morfología ofrece dos ventajas principales en comparación con las capas: su alta relación superficie-volumen y su mayor calidad cristalina, ambas beneficiosas p…
Non-resonant Raman spectroscopy of individual ZnO nanowires via Au nanorod surface plasmons
We present a non-resonant Raman spectroscopy study of individual ZnO nanowires mediated by Au nanorod surface plasmons. In this approach, selective excitation of the plasmonic oscillations with radiation energy below the semiconductor bandgap was used to probe surface optical modes of individual ZnO nanowires without simultaneous excitation of bulk phonons modes or band-edge photoluminescence. The development of a reproducible method for decoration of nanowires with colloidal Au nanorods allowed performing an extensive statistical analysis addressing the variability and reproducibility of the Raman features found in the hybrid nanostructures. An estimated field enhancement factor of 103 was…