Morphology and arrangement of InN nanocolumns deposited by radio-frequency sputtering: Effect of the buffer layer

摘要: Abstract We present the structural and optical properties of (0001)-oriented nanocolumnar films InN deposited on c -sapphire substrates by radio-frequency reactive sputtering. It is observed that column density dimensions are highly dependent growth parameters buffer layer. investigate four layers consisting (i) 30 nm low-growth-rate InN, (ii) AlN unbiased substrate (us), (iii) reverse-biased (bs), (iv) a 60-nm-thick bilayer 30-nm-thick bs-AlN top us-AlN. Differences in layer nucleation process due to induce variations range (2.5–16)×10 9  cm −2 , diameter 87–176 nm. Best results terms mosaicity obtained using layer, which leads full width at half-maximum InN(0002) rocking curve 1.2°. A residual compressive strain still nanocolumns. All samples exhibit room temperature photoluminescence emission ~1.6 eV, an apparent band gap ~1.7 eV estimated from linear transmittance measurements.