*Reporter：Dr. Ali Imran

*Time： 9：00 ~   12:00 at Apr. 9st, 2024.

*Place：Centre For   Quantum Physics   229

*Contact Person: Professor   Yang

*Abstract:

The demand for imaging devices has   surged exponentially during the last decade owing to their exceptionally high   quality and low noise imaging. However, they are still confronting the   performance constraints of high operation power, low speed, and limited   charge integration. In the present research work, we demonstrate the gateless   image sensing based on the electric-dipole gated phototransistor without   external gate bias by using high-k dielectric material. The device   integrates the photovoltaic, field effect, and tunable fermi level properties   of Si, HfO_2, and Graphene to create a non-destructive readout   system. The sensor exhibits remarkable performance in the broadband spectrum   range (266-1342 nm) at a low drain bias voltage of 0.5 V. The high values of   responsivity, external quantum efficiency, and detectivity of 3.7×10³   A W^-1, 0.72×10⁴ and 6.20×10¹³ cmHz^½   W^-1, respectively for 800 nm wavelength and   3.3×10³ A W^-1, 1.31×10⁴, and 5.61×10¹³   cmHz^½ W^-1, respectively for 400   nm wavelength are achieved. This discovery can eliminate the requirement for   gate terminal from commercial image sensing devices. The power efficient   features of the device can be fabricated at the industrial scale for the   future machine vision market.

*Profile：

Dr. Ali Imran is a Senior Research   Fellow at Zhejiang University, specializing in Optoelectronics devices such   as Photosensors, Photodetectors, Phototransistors, and Solar Cells. His work   focuses on Neuromorphic Vision Sensors fabrication, integrating 2D/3D   materials, high-k dielectrics, and Ferroelectrics. He excels in device   fabrication and characterization techniques, with research interests in HfO₂,   HAO, HZO, InAs, GaAs, InN, GaN, AlN, MoS₂, h-BN, and Graphene   based devices. He received the Distinguished International Researcher Award   from the Beijing Institute of Technology and has 32 research articles, 1   patent, and 1 book, published in respected journals and conferences. Dr.   Imran was a postdoctoral fellow at Peking University before joining Zhejiang   University in 2021, where he also collaborates with the Hangzhou Global   Innovation and Technology Center.