Stacking Mode-Driven Enhancement of Optoelectronic and Electrocatalytic Properties in Bilayer 2H MoS₂

Author(s)

Vishnu Aggarwal, Irfan H. Abidi, Jake Limb, Clara Kofler, Ajay Kumar Verma, Sindhu Priya Giridhar, Nethmi S.L. Dissanayake, Pargam Vashishtha, Jonathan O. Tollerud, Jianfeng Mao, Manoj Sehrawat, Tanish Gupta, Boopathiraja Kannan, Majid Panahandeh-Fard, Taimur Ahmed, Yuerui Lu, Jeffrey A. Davis, Salvy P. Russo, Jani Kotakoski, Enrico Della Gaspera, Cameron L. Bentley, Sunil Singh Kushvaha, Sumeet Walia

Abstract

The stacking orientation of bilayer two-dimensional (2D) materials introduces an additional degree of freedom that can profoundly influence their electronic, optoelectronic, and electrochemical properties. While stacking-engineered phenomena such as ferroelectricity, superconductivity, and second harmonic generation have been widely studied in bilayer molybdenum disulfide (MoS₂), their impact on functional device performance, particularly photoresponse and electrocatalysis, remains largely unexplored. Here, we investigate how the stacking configuration governs the optoelectronic and electrocatalytic behavior of bilayer MoS₂, focusing on the two stable stacking orders: 2H and 3R synthesized via chemical vapor deposition (CVD). Photodetection measurements reveal that 2H stacked bilayer MoS₂exhibits a remarkable two-orders-of-magnitude enhancement in photoresponsivity over its 3R counterpart, attributed to stronger interlayer coupling and more efficient charge transfer. Additionally, 2H MoS₂demonstrates enhanced field-effect transistor (FET) characteristics and achieves twice the hydrogen evolution reaction (HER) activity compared to 3R MoS₂. We employ scanning electrochemical cell microscopy (SECCM) to achieve spatially resolved mapping of electrocatalytic reactivity, offering the first direct nanoscale visualization of stacking-dependent HER activity. These findings underscore the crucial role of stacking orientation of atomic layers in tuning both optoelectronic and electrocatalytic properties, paving the way for stacking-engineered 2D materials in next-generation photodetectors and electrocatalytic devices.

Organisation(s)

Physics of Nanostructured Materials

External organisation(s)

RMIT University Vietnam, CSIR National Physical Laboratory, Academy of Scientific & Innovative Research (AcSIR), Monash University, Australian National University, Swinburne University of Technology

Journal

ACS Applied Materials and Interfaces

Volume

17

Pages

48658-48669

No. of pages

12

ISSN

1944-8244

DOI

https://doi.org/10.1021/acsami.5c11713

Publication date

08-2025

Peer reviewed

Yes

Austrian Fields of Science 2012

103015 Condensed matter, 103009 Solid state physics, 104008 Catalysis

Keywords

ASJC Scopus subject areas

General Materials Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/8e68fada-c035-4901-8c95-31d7d0bd8317