LAUSR

Abstract This paper reports on the unique approach adopted for the growth of vertically aligned two-dimensional AlN microwall arrays by a catalyst-free metal organic chemical vapor deposition (MOCVD) system via a two-step growth method. Wall-like structures are formed on the surface modified GaN/Al2O3 template using simple H3PO4 wet chemical etching, leading to growth of AlN microwall arrays. Large area and vertically aligned AlN microwalls with c-orientation could be grown on GaN/Al2O3 template, at the growth temperature and flow rate of 900 °C and 30 sccm respectively. The dimensions of AlN microwalls are 700 nm to 1.5 μm in diameter and up to 400 nm–500 nm in height. The structural, morphological and optical characterization of these samples have been carried out by HRXRD, SEM, XPS, Raman and Photoluminescence. AlN microwall arrays are wurtzite crystal structure with a small full width at half-maximum (352 arcsec) of (0002) X-ray rocking curve confirmed by High resolution X-ray diffraction. PL spectrum confirms defect related levels which enhances the visible emission. The experimental results have confirmed the two-dimensional AlN microwalls with high crystallinity and remarkable optical properties.