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Ultrahigh Photoluminescence Quenching (>90%) and Negative Photoresponse in Vertically Stacked Graphene/WSe2 van der Waals Heterojunctions
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DOI:10.1021/acsaelm.6c00961.png)
Abstract
En 中文
The interface effect plays a crucial role in determining the performance of van der Waals heterojunctions. Here, we fabricated graphene/WSe2 heterojunctions and investigated how graphene proximity dramatically alters their optical, electrical, and photoelectrical properties. It was found that graphene proximity induces ultrahigh photoluminescence quenching exceeding 90%, accompanied by substantial effective hole depletion in the WSe2 layer due to strong interfacial charge transfer. Photo illumination can further enhance charge transfer and charge accumulation at the interface. Electrical characterization shows that gate voltage effectively modulates interfacial charge transfer and thus the tunneling behavior. Notably, a transition from positive to negative photoresponse emerges when the effective tunneling barrier width is reduced below ∼1 nm, highlighting a tunneling-controlled photoresponse mechanism governed by the competition between interfacial charge transfer and bias-induced electric fields. These results provide comprehensive insights into interlayer charge transfer, exciton dynamics, and tunable photoelectrical properties in graphene/WSe2 heterostructures, paving the way for next-generation optoelectronic devices based on 2D vdW materials.
Keywords:
Charge transfer
Heterostructures
Layers
Tungsten diselenide
Two dimensional materials
van der Waals heterojunction
interface effect
tungsten selenide
graphene
photoluminescence quenching
Journal
IF:
4.7
Papers:
5.0K
Citations:
1.4W

