a
Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, 40-1 South Beijing Road, Urumqi 830011, China
E-mail: slpan@ms.xjb.ac.cn
;
Fax: (+86)-991-3838957
;
Tel: (+86)-991-3674558
b
Graduate School of Chinese Academy of Sciences, Beijing 100049, China