Energy-band engineering for improved charge retention in fully   self-aligned double floating-gate single-electron memories
  We present a new fully self-aligned single-electron memory with a single pair of nano floating gates, made of different materials (Si and Ge). The energy barrier that prevents stored charge leakage is induced not only by quantum effects but also by the conduction-band offset that arises between Ge and Si. The dimension and position of each floating gate are well defined and controlled. The devices exhibit a long retention time and single-electron injection at room temperature. 
Xiaohui Tang, Christophe Krzeminski, Aur\'elien Lecavelier des   Etangs-Levallois, Zhenkun Chen, Emmanuel Dubois, Erich Kasp...
cond-mat.mtrl-sci quant-ph