1. Department of Microelectronic Science and EngineeringNingbo UniversityNingbo315211People's Republic of China
2. National Key Laboratory of ASICHebei Semiconductor Research InstituteShijiazhuang050051People's Republic of China
3. College of SciencesXi'an Shiyou UniversityXi'an710065People's Republic of China
4. National Lab of Solid State MicrostructuresNanjing UniversityNanjing210093People's Republic of China