Formation mechanism and photoluminescence of AlN nanowhiskers

Aluminium nitride (AlN) nanowhiskers were synthesized on Si substrate by an oxide-assisted vapour transport and condensation method at 900 °C. Electron scanning microscope observations reveal that the whisker-like nanostructured architectures are composed of nanotips growing out from the surfaces of central sphere-like cores. The stem diameter of the nanotip is ∼100 nm and decreases with increasing distance from the core. The formation mechanism of the nanowhiskers is discussed on the basis of structural characterization. It is inferred that Fe2O3 plays an important role in the relatively low temperature growth of the AlN nanowhiskers. The photoluminescence of the nanowhiskers shows a broad blue luminescence band which can be Gaussian divided into three subbands. Spectral examinations and analysis reveal that the three subbands are connected with nitrogen vacancy, oxygen impurity and surface luminescence, respectively. The successful growth of AlN nanowhiskers would provide significant applications in modern optoelectronic and luminescence nanodevices.