^pKey;
Laboratory;
of;
Electronic;
Measurement;
Technology,;
North;
University;
of;
China,;
Taiyuan;
030051,;
China;
^pKey;
Laboratory;
of;
Electronic;
Thin;
Films;
and;
Integrated;
Devices,;
University;
of;
Electronic;
Science;
and;
Technologyof;
China,;
Chengdu;
641500,;
China;