Metal-oxide-semiconductor memory capacitors composed of dual-layer nanocrystalline ZnO embedded zirconium-doped hafnium oxide high-k film were fabricated, characterized, and compared with those with the single-layer nanocrystalline ZnO embedded sample. Distinct layers of discretely dispersed nanocrystalline dots embedded in the amorphous high-k matrix were observed. The nanocrystalline ZnO dots trap many electrons. The dual-layer sample not only drastically increases the charge storage density but also improves the charge trapping speed due to the coulomb blockade effect. This is a potentially important gate dielectric structure for high density, high speed nonvolatile memories.