Research On The Preparation Of Carbon-based Low-dimentional Nanocomposite Photodetectors And Their Photoelectric Response

As an important device,which is used to convert optical information to electrical information,the photodetector plays an important role in a varitiy of areas in modern life.For example,photodetections in ultraviolet band can be used for astronomical observa-tions and non-line-of-sight communications.The photodetection of visible light impels the era of the digital photography.Photodetectors in the infrared band are widely used in night visions,remote sensings and other national security surveillance fields.Detections of terahertz light have opened up applications in the medical imaging,food monitoring and security.The emergence of nanomaterials brings new oppotunities for the miniaturiza-tion and integration of photodetectors.Carbon-based nanomaterials such as graphene and carbon nanotubes have been recognized as the most potential photoelectronic materials for the next generation photodetectors due to their superior optical,electrical and thermal properties.Among various photodetectors made of carbon-based nanomaterials,one cata-groy uses the outstanding photoelectric properties of carbon-based nanomaterials them-selves,while the other one combines carbon-based nanomaterials with other materials to make use of the common advantages to prepare composite photoelectric devices.There are many different kinds of photoelectric detectors with various performances.However,a prominent problem that most photodetectors have is that it is difficult to combine the capabilities of the ultra-wide band detection,high performance,high sensitivity,etc.As a result,there is still a long way to go to prepare detectors that can meet all the performance requirements.This thesis aims to broaden the detecting band,improve the detection performance and enhance the sensitivity.Based on the advantages of low carbon nanomaterials such as carbon nanotubes,graphene and graphene derivatives,the reduced graphene oxide in the field of photoelectric detection,by combining them with super ionic conduc-tor film and metal film,the“asymmetric metal/suspended carbon nanotube film”com-posite nanostructures,“Rb Ag₄I₅/suspended monolayer graphene”composite nanostruc-tures and“asymmetric metal/suspended reduced graphene oxide thin film”composite nanostructures are prepared.Their photoelectric response and the underlying mecha-nism are systematically investigated.Among which,the“Rb Ag₄I₅/suspended monolayer graphene”composite nanostructures with silver ions in superionic effect on the regulation of the electrons in graphene realize photoelectric response ranging from the ultraviolet to infrared band.“asymmetric metal/suspended carbon nanotube film”and“asymmetric metal/suspended reduced graphene oxide thin film”composite nanostructures realize the ultra-wideband self power supply ranging from the ultraviolet-visible-infrared-terahertz band based on photothermoelectric effects.Meanwhile,the three kinds of structures shows improvements of response with orders of manitude compared with previous re-ported devices.In addition,the photoelectric detection response mechanism of the three structures are also explored,respectively,which laid foundations for the subsequent op-timization of structures to further improvements.To sum up,this thesis design and fabicate three novel photoelectric device based on the low carbon compounds.The improvements in detection band,performance,detection sensitivity and so on have obtained certain achievements and have considerable potential,which can be a meaningful reference for further developments of photoelectric detectors based on carbon nanomaterials.