Metallic-Phase-Fe$_3$GaTe$_2$ Enabled Interface Engineering for Self-Powered and High-Gain WS$_2$ Photodetectors

Wajid Ali; Ming Huang; Juan Li; Jianhua Huang; Liuli Yang; Sajid Ur Rehman; Chinmay K. Mohanty; Zahir Muhammad; Ziwei Li; Maciej R. Molas

arXiv · 2609.07295

Metallic-Phase-Fe$_3$GaTe$_2$ Enabled Interface Engineering for Self-Powered and High-Gain WS$_2$ Photodetectors

Wajid Ali·Ming Huang·Juan Li·Jianhua Huang·Liuli Yang·Sajid Ur Rehman·Chinmay K. Mohanty·Zahir Muhammad·Ziwei Li·Maciej R. Molas

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Abstract

Two-dimensional transition-metal dichalcogenides offer strong light-matter interaction but suffer from inefficient carrier separation and contact-related losses in photodetectors. Here, we demonstrate a high-gain WS$_2$/Fe$_3$GaTe$_2$ van der Waals heterostructure photodetector, where metallic Fe$_3$GaTe$_2$ serves as an active interfacial contact. The work-function mismatch, together with interfacial charge redistribution and asymmetric contact geometry, contributes to a built-in field that supports self-powered photodetection at zero bias. Under 450 nm illumination, the device delivers a zero-bias responsivity of 23.5 A/W and an apparent external quantum efficiency of 6.4 x 10$^3$%. At -1 V biasing, the heterostructure exhibits photoresponse at 450, 520 and 633 nm, achieving a responsivity of 9.7 x 10$^3$ A/W and a noise derived specific detectivity of 2.3 x 10$^13$ Jones at 100 Hz under 450 nm illumination. The high photoresponse is attributed to interfacial carrier separation, efficient extraction, and a likely contribution from trap-assisted photogating in multilayer WS$_2$. These results establish Fe$_3$GaTe$_2$-enabled interface engineering as an effective route for self-powered, highly sensitive 2D photodetectors.

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Wajid Ali, Ming Huang, Juan Li, Jianhua Huang, Liuli Yang, Sajid Ur Rehman, Chinmay K. Mohanty, Zahir Muhammad, Ziwei Li, Maciej R. Molas. 2026-09-07. Metallic-Phase-Fe$_3$GaTe$_2$ Enabled Interface Engineering for Self-Powered and High-Gain WS$_2$ Photodetectors. https://arxiv.org/abs/2609.07295

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