title: Regulating infrared photoresponses in reduced graphene oxide phototransistors by defect and atomic structure control.
abstract: Defects play significant roles in properties of graphene and related device performances. Most studies of defects in graphene focus on their influences on electronic or luminescent optical properties, while controlling infrared optoelectronic performance of graphene by defect engineering remains a challenge. In the meantime, pristine graphene has very low infrared photoresponses of ~0.01 A/W due to fast photocarrier dynamics. Here we report regulating infrared photoresponses in reduced graphene oxide phototransistors by defect and atomic structure control for the first time. The infrared optoelectronic transport and photocurrent generation are significantly influenced and well controlled by oxygenous defects and structures in reduced graphene oxide. Moreover, remarkable infrared photoresponses are observed in photoconductor devices based on reduced graphene oxide with an external responsivity of ~0.7 A/W, at least over one order of magnitude higher than that from pristine graphene. External quantum efficiencies of infrared devices reach ultrahigh values of ~97%, which to our knowledge is one of the best efficiencies for infrared photoresponses from nonhybrid, pure graphene or graphene-based derivatives. The flexible infrared photoconductor devices demonstrate no photoresponse degradation even after 1000 bending tests. The results open up new routes to control optoelectronic behaviors of graphene for high-performance devices.
authors.affiliation: WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8578, Japan. hxchang@wpi-aimr.tohoku.ac.jp
authors.forename: Haixin
authors.initials: H
authors.lastname: Chang
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Sun
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Saito
authors.forename: Qinghong
authors.initials: Q
authors.lastname: Yuan
authors.forename: Han
authors.initials: H
authors.lastname: Zhang
authors.forename: Jinhua
authors.initials: J
authors.lastname: Li
authors.forename: Zhongchang
authors.initials: Z
authors.lastname: Wang
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujita
authors.forename: Feng
authors.initials: F
authors.lastname: Ding
authors.forename: Zijian
authors.initials: Z
authors.lastname: Zheng
authors.forename: Feng
authors.initials: F
authors.lastname: Yan
authors.forename: Hongkai
authors.initials: H
authors.lastname: Wu
authors.forename: Mingwei
authors.initials: M
authors.lastname: Chen
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ikuhara
mesh_terms: D003460:Crystallization / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry* / Q000528:radiation effects; D007259:Infrared Rays; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000295:instrumentation*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry* / Q000528:radiation effects; D010316:Particle Size; D010783:Photometry / Q000295:instrumentation*; D014173:Transistors, Electronic
chemical_list: D010087:Oxides; D006108:Graphite