Pulsed layer growth of AlInGaN nanostructures

A pulsed layer growth mode in the metal-organic vapor phase epitaxy (MOVPE) was used to fabricate excellent quality AlInGaN nanostructures. The amount of material was varied, resulting in AlInGaN layer thicknesses between nominally 1.5 nm and 6 nm, respectively. We have analyzed the material properties by X-ray diffraction (XRD) as well as photoluminescence (PL) spectroscopy. The observed XRD-spectra and the PL intensity show the high quality of the deposited material. By analyzing the PL spectra we have found an energetic shift of the resonance lines from 2.65 eV to 3.33 eV with decreasing well thickness. We attribute this shift mainly to the presence of internal electric fields at the AlIn-GaN/GaN interface. Power-dependent and time resolved PL experiments confirm this observation. Comparing the luminescence at elevated temperatures, the pulsed layer epitaxy structures reveal a much higher intensity as the conventional grown samples. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)