[1
]State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic
Science and Engineering, University of Electronic Science and Technology of China,
Chengdu 610054, China
[2
]School of Materials Science and Engineering, Pennsylvania State University, State
College, Pennsylvania 16802, United States
[3
]Department of Bioengineering, University of California, Los Angeles, Los Angeles,
California 90095, United States