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Silicon (Si) photodetectors do not efficiently capture photons in the UV region: this has been a major impediment to their application in several areas. However, quantum dots (QDs), which convert higher-energy photons into lower-energy photons via spectral downshifting, have emerged as promising candidates for enhancing the UV response of silicon photodetectors. In this study, we investigate the performance of Si photodetectors in the form of sensitized perovskite (CsPbBr3) quantum dots and compare them with core-shell (CdZnS/ZnS) quantum dots for spectral downshifting applications. Using monolithic integration of quantum dots over the silicon photodetector surface, we systematically analyze their electrical and optical characteristics to elucidate the impact of quantum dot structures on device performance. Spectral responsivity measurements reveal a significant enhancement in detector performance over a broad spectral range (300 nm - 1100 nm) after sensitization with quantum dots. Reflectance studies suggest that apart from spectral downshifting, the quantum dot layers act as anti-reflection coatings, contributing to overall performance enhancement. Additionally, current-voltage characteristics indicate the formation of a space charge region at the Si-quantum dot interface, further enhancing device performance. Further opto-electronic testing demonstrates the superior performance and stability of CdZnS/ZnS core-shell QD-sensitized devices compared to perovskite CsPbBr3 QD-devices. Our study provides valuable insights into the design and optimization of Si photodetectors with improved sensitivity and extended spectral response.

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• Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International
  

  © 2024. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/

Keyword: quantum dot, spectral downshifting, photodetector, solution-processed, silicon

Date published: 2024-06-03

Publisher: Elsevier BV

Journal:

• Nano Energy (ISSN: 22112855) vol. 128 109832

Funding:

Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4679

First published URL: https://doi.org/10.1016/j.nanoen.2024.109832

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Updated at: 2024-08-23 14:00:21 +0900

Published on MDR: 2026-06-03 09:12:34 +0900