This study focused on the evolution of growth front about AlN growth on nano-patterned sapphire substrate by metal-organic chemical vapor deposition.The substrate with concave cones was fabricated by nano-imprint lith...This study focused on the evolution of growth front about AlN growth on nano-patterned sapphire substrate by metal-organic chemical vapor deposition.The substrate with concave cones was fabricated by nano-imprint lithography and wet etching.Two samples with different epitaxy procedures were fabricated,manifesting as two-dimensional growth mode and three-dimensional growth mode,respectively.The results showed that growth temperature deeply influenced the growth modes and thus played a critical role in the coalescence of AlN.At a relatively high temperature,the AlN epilayer was progressively coalescence and the growth mode was two-dimensional.In this case,we found that the inclined semi-polar facets arising in the process of coalescence were{112^-1}type.But when decreasing the temperature,the{112^-2}semi-polar facets arose,leading to inverse pyramid morphology and obtaining the three-dimensional growth mode.The 3 D inverse pyramid AlN structure could be used for realizing 3 D semi-polar UV-LED or facet-controlled epitaxial lateral overgrowth of AlN.展开更多
基金supported by the National Key R&D Program of China (No. 2016YFB0400800)the National Natural Sciences Foundation of China (Grant Nos. 61875187, 61527814, 61674147, U1505253)+1 种基金Beijing Nova Program Z181100006218 007Youth Innovation Promotion Association CAS 2017157
文摘This study focused on the evolution of growth front about AlN growth on nano-patterned sapphire substrate by metal-organic chemical vapor deposition.The substrate with concave cones was fabricated by nano-imprint lithography and wet etching.Two samples with different epitaxy procedures were fabricated,manifesting as two-dimensional growth mode and three-dimensional growth mode,respectively.The results showed that growth temperature deeply influenced the growth modes and thus played a critical role in the coalescence of AlN.At a relatively high temperature,the AlN epilayer was progressively coalescence and the growth mode was two-dimensional.In this case,we found that the inclined semi-polar facets arising in the process of coalescence were{112^-1}type.But when decreasing the temperature,the{112^-2}semi-polar facets arose,leading to inverse pyramid morphology and obtaining the three-dimensional growth mode.The 3 D inverse pyramid AlN structure could be used for realizing 3 D semi-polar UV-LED or facet-controlled epitaxial lateral overgrowth of AlN.
