Synthesis of Ultrathin Composition Graded Doped Lateral WSe2/WS2 Heterostructures.
ACS Appl Mater Interfaces
; 9(39): 34204-34212, 2017 Oct 04.
Article
em En
| MEDLINE
| ID: mdl-28891290
ABSTRACT
Lateral transition-metal dichalcogenide and their heterostructures have attracted substantial attention, but there lacks a simple approach to produce large-scaled optoelectronic devices with graded composition. In particular, the incorporation of substitution and doping into heterostructure formation is rarely reported. Here, we demonstrate growth of a composition graded doped lateral WSe2/WS2 heterostructure by ambient pressure chemical vapor deposition in a single heat cycle. Through Raman and photoluminescence spectroscopy, we demonstrate that the monolayer heterostructure exhibits a clear interface between two domains and a graded composition distribution in each domain. The coexistence of two distinct doping modes, i.e., interstitial and substitutional doping, was verified experimentally. A distinct three-stage growth mechanism consisting of nucleation, epitaxial growth, and substitution was proposed. Electrical transport measurements reveal that this lateral heterostructure has representative characteristics of a photodiodes. The optoelectronic device based on the lateral WSe2/WS2 heterostructure shows improved photodetection performance in terms of a reasonable responsivity and a large photoactive area.
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MEDLINE
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En
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2017
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Article