Investigation Of Photoelectronic Application Based On Graphene

Graphene has been widely investigated and used in device because of its unique electrical and photonic properties. However, owing to its zero band gap and low light absorption, pure graphene has been limited in many high performance photoelectronic applications. In order to extend application of graphene, combining graphene with other materials is a good solution. This dissertation is aiming to achieve high performance graphene electrophotonics by combining with silicon and organic halide perovskite, which can be briefly introduced as following:(1) We propose a kind of top-grid solar cell structure base on graphene/crystal silicon for the first time in this dissertation. The effect of oxidation treatment as well as device area to solar cell performance was systematically studied. The best solar cell performance can achieve 5.9% efficiency without antireflection layer. This kind device can avoid complex fabrication process and be compatible to traditional crystal silicon technology, promising a low cost, large area and high performance commercial production.(2) Photodetector based on perovskite nanoparticles/graphene hybrid film was systematically investigated in this thesis, which can achieve a high photo-resposivity over 6x106 A/W and a lager photo-conductive gain up to 109. Our study shows that perovskite nanoparticles can trap photo-induced carriers and reduce bulk recombination to increase device performance. Moreover, fast crystallization deposition method was adopted to control size and distribution of perovskite nanoparticles in order to optimize device performance.(3) Single perovskite nanowire photodetetor was successfully fabricated through solution process. The device show fast speed and broad band response with a high performance of 130 A/W at 405 nm. The current light on/off ration and detectivity can reach 4.8x103 and 2.9x1012 Jones, respectively.(4) Scanning type near field microscopy(SNOM) and photocurrent mapping system were used to visualize the carrier distribution as well as transport process of perovskite-nanoparticle/graphene heterojunction with or without light illumination. The results can help us to analyze carrier transport process and understand the device working mechanism behind. These two methods may provide us a new way to study behaviors of photo-induced carrier under light illumination in a photoelectronic device.