Raman Imaging of a Single Gallium Nitride Nanowire: Pushing the Limits of Confocal Microscopy
Mapping of the nanowire was performed by recording step-spectra at every 200 nm with an integration time of 1s. By intensity integration of the [509-552 cm-1] spectral domain around the A1(TO) mode (530 cm-1), the variations of the Raman signal over the full nanowire are investigated.
One dimensional semiconductor-nanowires of the wide-bandgap gallium nitride (GaN) are prime candidates for nanoscale devices such as short wavelength emitter optoelectronic devices and high-power/high-temperature electronics. Subsequently, it is of importance to measure the homogeneity and the composition of such nanowires at the individual scale and to correlate them with the dimensions and optical properties of these strongly anisotropic materials.
In the present work, we have conducted high resolution Raman measurement on a single GaN nanowire using a confocal microscope in conjunction with a high resolution piezoelectric stage for an accurate and reproducible positioning.
In summary, we have performed a complete Raman polarized study of a single GaN nanowire using a confocal microscope together with a high resolution stage. The high spatial resolution of our Raman confocal instrument together with a piezoelectric stage demonstrates unambiguously the possibility to image the optical properties of nano-objects with a resolution better than 200 nm keeping the fill advantage of the polarization control under a confocal microscope.
