**Author details**

Rajendran Ramachandran1,2 and Fei Wang1,2,3\*

\*Address all correspondence to: wangf@sustc.edu.cn

1 Department of Electronic and Electrical Engineering, Southern University of Science and Technology, Shenzhen, China

2 Shenzhen Key Laboratory of 3rd Generation Semiconductor Devices, Shenzhen, China

3 State Key Laboratories of Transducer Technology, Shenzhen, China
