Synthesis and optical characterization of single-crystalline AlN nanosheets

Uniform and smooth AlN nanosheets were fabricated on Si substrates by a vapour-phase transport method, using Al powder and ammonia as the source materials. Their morphology and structure were examined by scanning and transmission electron microscopy, and X-ray diffraction. They have a perfect rectangular shape. The growth is favoured along the 〈 1 1 ̄ 00 〉 and 〈 0001 〉 crystallographic directions within the 〈 11 2 ̄ 0 〉 plane. Their growth mechanism is discussed on the basis of data gathered. The linewidth of E 2 (high) longitudinal optical phonon mode is about 7 cm−1, indicating their high quality. Their photoluminescence property is also investigated.