Engineering 2D Van der Waals Electrode via MBE Grown Weyl Semimetal 1T-WTe2 for Enhanced Photodetection in InSe

Biswajit Khan; Santanu Kandar; Taslim Khan; Kritika Bhattacharya; Nahid Chowdahury; Suprovat Ghosh; Pawan Kumar; Rajendra Singh; Samaresh Das

arXiv · 2502.13261

Engineering 2D Van der Waals Electrode via MBE Grown Weyl Semimetal 1T-WTe2 for Enhanced Photodetection in InSe

Biswajit Khan·Santanu Kandar·Taslim Khan·Kritika Bhattacharya·Nahid Chowdahury·Suprovat Ghosh·Pawan Kumar·Rajendra Singh·Samaresh Das

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Abstract

Achieving low contact resistance in advanced quantum electronic devices remains a critical challenge. With the growing demand for faster and energy-efficient devices, 2D contact engineering offers a promising solution. Beyond graphene, 1T-WTe2 has attracted attention for its excellent electrical transport, quantum phenomena, and Weyl semimetallic properties. Here, we demonstrate the direct wafer-scale growth of 1T-WTe2 via molecular beam epitaxy (MBE) and its use as a 2D contact for layered materials such as InSe. The 1T WTe2/InSe interface exhibits a barrier height nearly half that of conventional metal contacts, and its contact resistance is reduced by a factor of 21, effectively suppressing Fermi level pinning and enabling efficient electron injection. InSe/1T WTe2 photodetectors show broad photoresponsivity (0.14 to 217.58 A/W) under NIR to DUV illumination with fast rise/fall times of 42/126 ms, compared to lower responsivity (0.000865 A/W to 3.64 A/W) and slower response (150/144 ms) for InSe/Ti Au devices. The 1T WTe2/InSe devices thus exhibit approximately 60 times higher responsivity and 4 times faster response than conventional metal contacts. These results establish MBE-grown 1T-WTe2 as an effective 2D electrode, enhancing photodetection performance while simplifying device architecture, making it a strong candidate for next generation nanoelectronic and optoelectronic devices.

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Biswajit Khan, Santanu Kandar, Taslim Khan, Kritika Bhattacharya, Nahid Chowdahury, Suprovat Ghosh, Pawan Kumar, Rajendra Singh, Samaresh Das. 2025-02-18. Engineering 2D Van der Waals Electrode via MBE Grown Weyl Semimetal 1T-WTe2 for Enhanced Photodetection in InSe. https://arxiv.org/abs/2502.13261

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