Abstract
The effects of absorber structure–controlled by adjusting the thickness ratio of doped and undoped InGaAs layers–and metal-semiconductor interface treatment methods were investigated in waveguide-type UTC-PDs. Ultraviolet-ozone (UVO) and ammonia solution cleaning of the InGaAs surface improved the interface quality in terms of contact resistivity and bias-temperature stability. Nevertheless, devices cleaned using buffered oxide etchant (BOE) exhibited higher photoresponsivity and superior frequency characteristics. This phenomenon is attributed to the reduction of dark current (IDark) caused by the residual interfacial oxide layer at the metal/InGaAs interface. In contrast, the influence of absorber structure variation was negligible. These results demonstrate that the interface condition plays a more dominant role than absorber modification in determining device performance. Therefore, optimizing the interface condition while maintaining a high-quality oxide layer is essential for further enhancing UTC-PD performance.
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Acknowledgements
This work was supported by the Nano & Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (RS-2024-00411969), in part by the Electronics and Telecommunication Research Institute (ETRI) grant funded by the Korean government (25ZB1300).
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S.C.K. and J.C.C. contributed equally: conceptualization, fabrication, investigation, methodology, visualization, writing—original draft, writing—review and editing. E.S.L.: conceptualization, methodology, resources, writing—review and editing, and funding. D.W.P.: conceptualization, methodology, writing—review and editing, and funding.
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Kang, S.C., Cho, J.C., Lee, E.S. et al. Influence of metal–semiconductor interface treatments and absorber structure on the performance and reliability of uni-traveling-carrier photodiodes (UTC-PDs). Sci Rep (2026). https://doi.org/10.1038/s41598-025-34935-y
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DOI: https://doi.org/10.1038/s41598-025-34935-y
