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Layer‐Number‐Dependent Electronic and Optoelectronic Properties of 2D WSe 2 ‐Organic Hybrid Heterojunction
Author(s) -
Ji Jaehoon,
Choi Jong Hyun
Publication year - 2019
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201900637
Subject(s) - heterojunction , materials science , dopant , exciton , optoelectronics , photocurrent , photoluminescence , doping , nanotechnology , condensed matter physics , physics
One of the most attractive features of 2D WSe 2 is a tunability in its electronic and optoelectronic properties depending on the layer number. To harness such unique characteristics for device applications, high quality and easily processable heterojunctions are required and relevant layer‐number‐dependent properties must be understood. Herein, a study is reported on hybrid heterojunctions between 2D WSe 2 and organic molecules from one‐step solution chemistry and their layer‐number‐dependent properties. Eosin Y (EY) dye is selected as a p‐dopant and uniformly stacked on mechanically exfoliated WSe 2 flakes via van der Waals interaction, forming a hybrid heterojunction with a type II alignment. The EY‐WSe 2 heterojunction shows significantly enhanced currents compared to pristine WSe 2 with a lower barrier height and a longer effective screening length. The work function of the heterostructure is also lower than that of pristine WSe 2 . The efficient exciton dissociation and doping effect by EY are confirmed by photocurrent and photoluminescence measurements, where WSe 2 emission is markedly quenched by EY and exciton contribution decreases with layer number. These findings shed critical insights into layer‐number‐dependent electronic and optoelectronic properties of organic‐WSe 2 layers and also provide simple yet effective means to construct transition metal dichalcogenide‐based heterostructures, which should be valuable for developing layered 2D devices.