A double-stacked nanocrystal (DSNC) Hash memory is presented for improvement of both program/erase speed and data retention time. Four combinations of nickel (Ni) and gold (An) (Ni/Ni, Au/Au, Ni/Au, and Au/Ni) are used as charge storage DSNC materials and are compared from the perspective of memory performance, Through experimental results for P/E efficiency and retention time, the optimized energy band lineup for faster P/E, and longer charge retention is presented. A combination of a deep potential well at the top and a shallow potential well at the bottom exhibits optimized performance in P/E, and this combination also shows the longest data retention characteristics.