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Description:

Homojunctions are key elements in many mainstream electronic devices. However, conventional dopant-based ‘pn’ homojunctions are not easily achievable in new material families, such as the two-dimensional (2D) materials. Several recent 2D material studies have shown that, instead, lateral pn homojunctions can be electrostatically induced using back gates localized to either the source or drain contacts. Here, we demonstrate hBN-encapsulated bP dual-gate device which can form lateral pn homojunctions in either direction by switching the back gate configuration. Importantly, this study extends the state-of-the-art for this architecture by characterizing the photoresponse under infrared (λ = 2.2 µm) illumination. It is shown that when biased to form a homojunction the device exhibits the photovoltaic effect, resulting in a specific detectivity of 8.5 × 108 cm Hz1/2 W-1 at 77 K under short-circuit conditions, and an open circuit photovoltage up to 175 mV at 77 K. Further, it is shown that the device can also be operated in a photoconductive mode of operation allowing a high responsivity of 0.55 A W-1 (VDS = -500 mV, 77 K). As such, this reconfigurable device can be switched between photovoltaic and photoconductive modes of operation to prioritize low noise or high responsivity.

Rights:

• Creative Commons BY-NC Attribution-NonCommercial 4.0 International
  

Keyword: Homojunctions, 2D materials, photoresponse

Date published: 2024-05-07

Publisher: Wiley

Journal:

• Advanced Functional Materials (ISSN: 16163028) vol. 34 issue. 32 2316000

Funding:

• Australian Research Council DE210101129
• Australian Research Council DP210103428
• Australian Research Council DP200101345

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1002/adfm.202316000

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Updated at: 2025-02-14 12:31:30 +0900

Published on MDR: 2025-02-14 12:31:30 +0900