Nano-floating gate memory devices were fabricated by using nickel nanocrystals as a charge-trapping portion embedded into Al2O3 thin films. Ni nanocrystals were prepared via a thermal reduction of nanoscale NiO layers deposited by atomic layer deposition. Although the continuous deposition of insulating Al2O3 and semiconducting NiO thin films allowed the facile fabrication of charge-trap, the corresponding retention feature suffers from inferior charge trapping/detrapping. On the other hand, the Ni nanocrystals enhanced the retention behavior and exhibited the largest memory window of 13.8 V with the stored charge density of 2.5 x 10(13) traps/cm(2), probably due to the isolated formation of charge-trapping centers. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3583534] All rights reserved.