State Key Laboratory of Functional Materials for Informatics;
Laboratory of Nanotechnology;
Shanghai Institute of Micro-System and Information Technology;
Chinese Academy of Sciences;
Shanghai 200050;
Graduate School of the Chinese Academic of Sciences;
Beijing 100049;
Silicon Storage Technology;
lnc.;
1171 Sonora Court;
Sunnyvale;
CA 94086;
U.S.A.;