Alpha-In₂Se₃ Based Photodetector Units Co-modulated By Ferroelectric Polarization And Pt Nanodot

Photodetector is a device that converts optical signals into electrical signals which plays an irreplaceable role in social life and production.They have great application prospects in memories,capacitors,actuators,transistor,sensors,and especially nanophotodetectors,due to their unique physical properties including novel electronic,magnetic,thermal,and optical properties.With the development of society,there is a growing demand for the miniaturization,wearability,wide detection band and high sensitivity of optoelectronic devices.However,it is difficult for the commercial silicon-based optoelectronic devices to realize these characteristics.Two-dimensional layered nano-photoelectric materials combined with ferroelectric layers show excellent photoelectric performance,but the critical size effect of ferroelectric layers limits the miniaturization of devices.At present,there is little research work focusing on the connection between two-dimensional intrinsic ferroelectric and photoelectric.Two-dimensional?-In₂Se₃ is a widely studied material,which has suitable optical band gap?visible light range?and strong light absorption characteristics.Its excellent photoelectric characteristics provide a good material basis for constructing high performance photodetectors.In this work,the mechanical exfoliation process of two-dimensional?-In₂Se₃ was optimized firstly,and high-quality?-In₂Se₃ nanosheets were prepared.Secondly,the effect of polarization voltage on the light-dark current switching ratio of?-In₂Se₃ based photodetector unit was studied.Finally,platinum nanoparticles were used to modify the surface of two-dimensional?-In₂Se₃,which greatly enhanced the light absorption of?-In₂Se₃ based photodetector unit.All detailed research contents and results are as follows:?1?The preparation and characterization of?-In₂Se₃ nanosheets.The?-In₂Se₃nanosheets were prepared by mechanical exfoliation method.The stripping process such as heating table assisted and directional separation at an oblique angle of 45°were optimized.The morphology,domain structure and composition of the prepared nanosheets were characterized by XRD,Raman,AFM,SEM and other instruments.The results show that the large-area,high-quality ferroelectric?-In₂Se₃ nanosheets were successfully prepared.?2?Study on?-In₂Se₃ based photodetector units with ferroelectric modulation.A planar double-ended?-In₂Se₃ based photodetector unit was prepared using a small ion sputtering instrument,and its photoelectric detection performance was tested.The results show that the photodetection performance of the detector unit is improved by high-voltage polarization.When the detector unit is illuminated by a solar simulator with a full-wavelength visible light and a power of 32.6 m W/cm²,A current switching ratio of 400%is obtained,and the response speed of the detector is 44.5 ms/54.2 ms.After high-voltage polarization of the detector unit,the current switching ratio can be as high as 10⁵%,and the response speed of the detector is 46.3 ms/20.4 ms.?3?Study on the performance of?-In₂Se₃ based photodetector unit modified by platinum nanoparticles.A Pt nanoparticle-modified detector unit was prepared by covering a mask plate with a circular hole array and its photoelectric detection performance was tested.The results showed that the surface of the Pt nanoparticle-modified?-In₂Se₃ nanosheet can significantly enhance the photoelectric detection performance.The detector unit achieves a current switching ratio of up to 2×10⁹%,the response speed of the detector is 118 ms/51.7 ms,and the light responsivity of the device unit reaches 2000 A/W.