title: GaAs/AlGaAs nanowire photodetector.
abstract: We demonstrate an efficient core-shell GaAs/AlGaAs nanowire photodetector operating at room temperature. The design of this nanoscale detector is based on a type-I heterostructure combined with a metal-semiconductor-metal (MSM) radial architecture, in which built-in electric fields at the semiconductor heterointerface and at the metal/semiconductor Schottky contact promote photogenerated charge separation, enhancing photosensitivity. The spectral photoconductive response shows that the nanowire supports resonant optical modes in the near-infrared region, which lead to large photocurrent density in agreement with the predictions of electromagnetic and transport computational models. The single nanowire photodetector shows a remarkable peak photoresponsivity of 0.57 A/W, comparable to large-area planar GaAs photodetectors on the market, and a high detectivity of 7.2 × 10(10) cm·Hz(1/2)/W at λ = 855 nm. This is promising for the design of a new generation of highly sensitive single nanowire photodetectors by controlling the optical mode confinement, bandgap, density of states, and electrode engineering.
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 50 Nanyang Ave, Singapore 637371.
authors.forename: Xing
authors.initials: X
authors.lastname: Dai
authors.forename: Sen
authors.initials: S
authors.lastname: Zhang
authors.forename: Zilong
authors.initials: Z
authors.lastname: Wang
authors.forename: Giorgio
authors.initials: G
authors.lastname: Adamo
authors.forename: Hai
authors.initials: H
authors.lastname: Liu
authors.forename: Yizhong
authors.initials: Y
authors.lastname: Huang
authors.forename: Christophe
authors.initials: C
authors.lastname: Couteau
authors.forename: Cesare
authors.initials: C
authors.lastname: Soci