The Study Of Multifunctional Photodetectors Based On Two-dimensional Materials And Heterostructures

Widely recognized for its unique properties,graphene has been the focus of research since its discovery via mechanical exfoliation in 2004.Similarly,other two-dimensional materials,such as transition metal sulfides,perovskites,black phosphorus,and topological insulators,have been discovered and studied for their optoelectronic properties.However,there is still much research needed to develop practical and efficient optoelectronic devices based on these materials.In particular,with the increasing density and complexity of optical information,the next generation of photodetectors must be capable of detecting multiple types of optical information beyond just intensity and wavelength.Designing two-dimensional material optoelectronic detectors that meet these requirements is a significant challenge for the coming decades.Graphene remains the most promising two-dimensional material for practical application due to its self-limiting effect during the synthesis process,allowing large-size monolayer films to be realized.Integrating graphene with well-developed semiconductors is a practical strategy for achieving high-performance,multifunctional optoelectronic devices.Moreover,the unique van der Waals interface of two-dimensional materials enables various and flexible combinations of heterostructures without considering lattice matching.Therefore,research on graphene heterostructures serves as an efficient approach for studying the generation,transportation,and recombination of photogenerated carriers in two-dimensional material systems.It can also significantly improve the optoelectronic properties of devices and exhibit novel behaviors,as often seen in complex silicon-based circuit designs.This thesis focuses on the following research on graphene heterostructure optoelectronic devices with unconventional optical information detection capabilities:In this thesis,graphene heterostructure optoelectronic devices with unconventional optical information detection capabilities were researched.The main objectives were:1.The design of a large-size infrared position-sensitive detector based on the graphene-germanium Schottky junction,which exhibited high optoelectronic responsivity range from visible to near-infrared.The high mobility of graphene enabled millimeter-scale lateral carriers transportation with sub-microns position sensitivity.The device showed microsecond optoelectronic response time and could achieve non-contact optical measurements such as small angle measurement,high-frequency signal acquisition,and infrared target trajectory tracking when combined with special designed optical systems.2.The design of a’time-divisional’position-sensitive detector by combining graphene with conventional semiconductors.This detector allows multi-target imaging and tracking on a single position-sensitive detector,with a theoretical detection frame rate of 62,000 fps and sub-micron spatial resolution.In addition,high frequency detection capabilities enabled frequency-related image preprocessing,such as multi-channel target detection and image denoising in complex environments.The’time-divisional’position-sensitive detector provides a parallel approach to traditional array detectors.3.The construction of a two-dimensional graphene-ruthenium disulfide-graphene heterostructure,which achieved an optoelectronic resistive random-access memory with a high sensitivity of 5×10~4 A/W.The device provides an approach to modeling interfacial defects through gate control,which enables the controllable prolongs of photogenerated carriers’lifetime.The device shows both long-term and short-term light plasticity in the detection of polarization light.This paper promotes the technological development of non-contact optical detection.Position detection and polarization detection are important in the field of non-contact optical measurement.By improving the performance of the devices,the accuracy and reliability of relevant applications can be improved.The position-sensitive detector based on the lateral photovoltaic effect has unique advantages over widely used array-type detectors in some application scenarios,therefore the performance and costs of existing systems can be optimized.