title: Dichroic spin-valley photocurrent in monolayer molybdenum disulphide.
abstract: The aim of valleytronics is to exploit confinement of charge carriers in local valleys of the energy bands of semiconductors as an additional degree of freedom in optoelectronic devices. Thanks to strong direct excitonic transitions in spin-coupled K valleys, monolayer molybdenum disulphide is a rapidly emerging valleytronic material, with high valley polarization in photoluminescence. Here we elucidate the excitonic physics of this material by light helicity-dependent photocurrent studies of phototransistors. We demonstrate that large photocurrent dichroism (up to 60%) can also be achieved in high-quality molybdenum disulphide monolayers grown by chemical vapour deposition, due to the circular photogalvanic effect on resonant excitations. This opens up new opportunities for valleytonic applications in which selective control of spin-valley-coupled photocurrents can be used to implement polarization-sensitive light-detection schemes or integrated spintronic devices, as well as biochemical sensors operating at visible frequencies.
authors.affiliation: School of Physical and Mathematical Sciences, Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Eginligil
authors.affiliation: School of Physical and Mathematical Sciences, Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Bingchen
authors.initials: B
authors.lastname: Cao
authors.affiliation: 1] School of Physical and Mathematical Sciences, Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore [2] Centre for Disruptive Photonic Technologies, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Zilong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: School of Physical and Mathematical Sciences, Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Shen
authors.affiliation: School of Physical and Mathematical Sciences, Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Chunxiao
authors.initials: C
authors.lastname: Cong
authors.affiliation: School of Physical and Mathematical Sciences, Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Jingzhi
authors.initials: J
authors.lastname: Shang
authors.affiliation: 1] School of Physical and Mathematical Sciences, Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore [2] Centre for Disruptive Photonic Technologies, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Cesare
authors.initials: C
authors.lastname: Soci
authors.affiliation: 1] School of Physical and Mathematical Sciences, Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore [2] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore [3] Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore.
authors.forename: Ting
authors.identifier: 0000000201132895
authors.initials: T
authors.lastname: Yu