A Proof-of-concept Study on Enhancing the Visible Photoresponse of RGO/ZnO Devices with PbS Quantum Dots
Main Article Content
Abstract
Hybrid structures of zinc oxide nanorods (ZnO NRs) and reduced graphene oxide (RGO) are a promising platform for photodetection applications, owing to their excellent charge transport pathways and high stability. However, their operational range is intrinsically limited to the ultraviolet (UV) spectrum due to the wide optical band gap of ZnO (~3.37 eV), restricting their applicability in broadband photodetection. To circumvent this issue, in this study, we introduce lead sulfide quantum dots (PbS QDs) decoration to the RGO/ZnO-based photodetector. The deposition of 2 mg mL-1 PbS QDs successfully broadened the light absorption capabilities, as evidenced by a decreased optical band gap from 3.19 to 3.13 eV. Consequently, the fabricated RGO/ZnO-PbS NRs heterostructure photodetector demonstrates a remarkable improvement in performance achieving a maximum photo-current of 292.06 µA, with a 19.5-fold increase in responsivity and photoconductive gain, and nearly three times higher in detectivity, when excited with 395 nm (800 µW) light source. Nonetheless, the device also maintains a repeatable signal pattern over several on/off cycles. Therefore, this work not only presents a highly effective path for engineering the spectral response of ZnO-based devices but also validates the pivotal role of PbS QDs in creating high-performance, broadband photodetectors for next-generation optoelectronic applications.
Keywords:
ZnO nanorods, PbS QDs, heterostructure, visible photodetector, tunable optical bandgap
References
[[1] Y. Shen, X. Wang, Z. Xie, C. Min, X. Fu, Q. Liu, M. Gong, X. Yuan, Optical Vortices 30 Years on: OAM Manipulation from Topological Charge to Multiple Singularities, Light: Science & Applications, Vol. 8, No. 90, 2019, pp. 1-29, https://doi.org/10.1038/s41377-019-0194-2.
[2] L. Allen, M. W. Beijersbergen, R. J. C. Spreeuw, J. P. Woerdman, Orbital Angular Momentum of Light and The Transformation of Laguerre-Gaussian Laser Modes, Physical Review A, Vol. 45, Issue 11, 1992, pp. 8185-8189, https://doi.org/10.1103/PhysRevA.45.8185.
[3] M. Padgett, R. Bowman, Tweezers with A Twist, Nature Photonics, Vol. 5, Issue 6, 2011, pp. 343-348, https://doi.org/10.1038/nphoton.2011.81.
[4] A. Kocyigit, K. Cicek, R. Topkaya, X. Cai, Integrated Vortex Beam Emitter Device for Optical Manipulation, Applied Optics, Vol. 59, Issue 10, 2020, pp. 3179-3182, https://doi.org/10.1364/AO.384838.
[5] M. Yoshida, Y. Kozawa, S. Sato, Subtraction Imaging by The Combination of Higher-Order Vector Beams for Enhanced Spatial Resolution, Optics Letters, Vol. 44, Issue 4, 2019, pp. 883-886, https://doi.org/10.1364/ol.44.000883.
[6] K. I. Willig, S. O. Rizzoli, V. Westphal, R. Jahn, S. W. Hell, STED Microscopy Reveals That Synaptotagmin Remains Clustered After Synaptic Vesicle Exocytosis, Nature, Vol. 440, Issue 7086, 2006, pp. 935-939, https://doi.org/10.1038/nature04592.
[7] J. Wang, J. Y. Yang, I. M. Fazal, N. Ahmed, Y. Yan, H. Huang, Y. Ren, Y. Yue, S. Dolinar, M. Tur, A. E. Willner, Terabit Free-Space Data Transmission Employing Orbital Angular Momentum Multiplexing, Nature Photonics, No. 6, 2012, pp. 488-496, https://doi.org/10.1038/nphoton.2012.138.
[8] L. Zhu, A. Wang, J. Wang, Free-Space Data-Carrying Bendable Light Communications, Scientific Report, No. 9, 2019, pp. 14969, https://doi.org/10.1038/s41598-019-51496-z.
[9] S. Syubaev, A. Zhizhchenko, A. Kuchmizhak, A. Porfirev, E. Pustovalov, O. Vitrik, Yu. Kulchin, S. Khonina, S. Kudryashov, Direct Laser Printing of Chiral Plasmonic Nanojets by Vortex Beams, Journal of Physics: Conference Series, Vol. 951, 2018, pp. 012025, https://doi.org/10.1088/1742-6596/951/1/012025.
[10] Y. Zhang, M. Agnew, T. Roger, F.S. Roux, T. Konrad, D. Faccio, J. Leach, A. Forbes, Simultaneous Entanglement Swapping of Multiple Orbital Angular Momentum States of Light, Nature Communications, No. 8, 2017, pp. 632, https://doi.org/10.1038/s41467-017-00706-1.
[11] H. Y. Tsai, H. I. Smith, R. Menon, Fabrication of Spiral-Phase Diffractive Elements Using Scanning-Electron-Beam Lithography, Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures,
No. 25, 2007, pp. 2068-2071, https://doi.org/10.1116/1.2806961.
[12] T. Jankowski, N. Bennis, P. Morawiak, D. C. Zografopoulos, A. Pakuła, M. Filipiak, M. Słowikowski, J. M. López. Higuera, J. F. Algorri, Optical Vortices by An Adaptive Spiral Phase Plate, Optics & Laser Technology, Vol. 176, 2024, pp. 111029, https://doi.org/10.1016/J.OPTLASTEC.2024.111029.
[13] Y. H. Kim, C. Y. Hwang, J. H. Choi, J. E. Pi, J. H. Yang, S. M. Cho, S. H. Cheon, G. H. Kim, K. Choi, H. O. Kim, W. J. Lee, H. B. Kang, C. S. Hwang, Development of High-Resolution Active Matrix Spatial Light Modulator, Optical Engineering, Vol. 57, No. 6, 2018, pp. 1, https://doi.org/10.1117/1.oe.57.6.061606.
[14] A. S. Ostrovsky, C. R. Parrao, V. Arrizón, Generation of the Perfect Optical Vortex Using A Liquid-Crystal Spatial Light Modulator, Optics Letters, Vol. 38, Issue 4, 2013, pp. 534-536, https://doi.org/10.1364/ol.38.000534.
[15] K. Qu, Q. Jia, N.J. Fisch, Plasma Q-Plate for Generation and Manipulation of Intense Optical Vortices, Physical Review E, Vol. 96, No. 5, 2017, pp. 053207, https://doi.org/10.1103/PhysRevE.96.053207.
[16] D. W. Prather, J. N. Mait, M. S. Mirotznik, Design of Binary Subwavelength Diffractive Lenses by Use of Zeroth-Order Effective-Medium Theory, Journal of the Optical Society of America A, Vol. 16, Issue 5, 1999,
pp. 1157-1167, https://doi.org/10.1364/JOSAA.16.001157.
[17] A. Filipkowski, Fabrication and Integration of Nanostructured Optical Devices, Engineering and Physical Sciences, 2015, http://hdl.handle.net/10399/4073 (accessed on: July 30th, 2025).
[18] K. Switkowski, A. Anuszkiewicz, A. Filipkowski, D. Pysz, R. Stepien, W. Krolikowski, R. Buczynski, Formation of Optical Vortices with All-Glass Nanostructured Gradient Index Masks, Optics Express, Vol. 25, No. 25, 2017, pp. 31443, https://doi.org/10.1364/oe.25.031443.
[19] F. Hudelist, J. M. Nowosielski, R. Buczynski, A. J. Waddie, M. R. Taghizadeh, Nanostructured Elliptical Gradient-Index Microlenses, Optics Letters, Vol. 35, Issue 2, 2010, pp. 130-132, https://doi.org/10.1364/ol.35.000130.
[20] R. Kasztelanic, N. T. Hue, D. Pysz, H. Thienpont, T. Omatsu, R. Buczynski, Free-Form Optical Fiber with A Square Mode and Top-Hat Intensity Distribution, Advanced Science, Vol. 11, Issue 33, 2024, pp. 2402886, https://doi.org/10.1002/advs.202402886.
[21] N. T. Hue, K. Switkowski, R. Kasztelanic, A. Anuszkiewicz, Optical Characterization of Single Nanostructured Gradient Index Vortex Phase Masks Fabricated by the Modified Stack-And-Draw Technique, Optics Communications, Vol. 463, 2020, pp. 125435, https://doi.org/10.1016/j.optcom.2020.125435.
[22] N. T. Hue, L. V. Bau, C. V. Bien, T. T. Hai. L.V. Hieu, R. Kasztelanic, R. Buczynski, Achromatic Nanostructured Phase Components for Micro-Optical Vortex Beam Generation, Journal of the Optical Society of America B,
Vol. 42, Issue 6, 2025, pp. 1194-1203, https://doi.org/10.1364/JOSAB.555732.
[23] CDGM, (n.d.). https://www.cdgmgd.com//database/toWebDatabase.htm?k=Products_Data&url=database (accessed on: July 30th, 2025).
[24] F. Hudelist, R. Buczynski, A. J. Waddie, M.R. Taghizadeh, Design and Fabrication of Nano-Structured Gradient Index Microlenses, Optics Express, Vol. 17, No. 5, 2009, pp. 3255-3263, https://doi.org/10.1364/oe.17.003255.
[25] R. Buczynski, A. Filipkowski, B. Piechal, N. T. Hue, D. Pysz, R. Stepien, A. Waddie, M.R. Taghizadeh, M. Klimczak, R. Kasztelanic, Achromatic Nanostructured Gradient Index Microlenses, Optics Express, Vol. 27, No. 7, 2019, pp. 9588, https://doi.org/10.1364/oe.27.009588.
[26] N. T. Hue, R. Kasztelanic, A. Filipkowski, D. Pysz, L.V. Hieu, R. Stepien, T. Omatsu, W. Krolikowski, R. Buczynski, Broadband Optical Vortex Beam Generation Using Flat-Surface Nanostructured Gradient Index Vortex Phase Masks, Scientific Reports, No. 13, 2023, pp. 20255, https://doi.org/10.1038/s41598-023-46871-w.
[27] K. Okamoto, Fundamentals of Optical Waveguides, Academic Press, 2006, pp. 329-383.
[2] L. Allen, M. W. Beijersbergen, R. J. C. Spreeuw, J. P. Woerdman, Orbital Angular Momentum of Light and The Transformation of Laguerre-Gaussian Laser Modes, Physical Review A, Vol. 45, Issue 11, 1992, pp. 8185-8189, https://doi.org/10.1103/PhysRevA.45.8185.
[3] M. Padgett, R. Bowman, Tweezers with A Twist, Nature Photonics, Vol. 5, Issue 6, 2011, pp. 343-348, https://doi.org/10.1038/nphoton.2011.81.
[4] A. Kocyigit, K. Cicek, R. Topkaya, X. Cai, Integrated Vortex Beam Emitter Device for Optical Manipulation, Applied Optics, Vol. 59, Issue 10, 2020, pp. 3179-3182, https://doi.org/10.1364/AO.384838.
[5] M. Yoshida, Y. Kozawa, S. Sato, Subtraction Imaging by The Combination of Higher-Order Vector Beams for Enhanced Spatial Resolution, Optics Letters, Vol. 44, Issue 4, 2019, pp. 883-886, https://doi.org/10.1364/ol.44.000883.
[6] K. I. Willig, S. O. Rizzoli, V. Westphal, R. Jahn, S. W. Hell, STED Microscopy Reveals That Synaptotagmin Remains Clustered After Synaptic Vesicle Exocytosis, Nature, Vol. 440, Issue 7086, 2006, pp. 935-939, https://doi.org/10.1038/nature04592.
[7] J. Wang, J. Y. Yang, I. M. Fazal, N. Ahmed, Y. Yan, H. Huang, Y. Ren, Y. Yue, S. Dolinar, M. Tur, A. E. Willner, Terabit Free-Space Data Transmission Employing Orbital Angular Momentum Multiplexing, Nature Photonics, No. 6, 2012, pp. 488-496, https://doi.org/10.1038/nphoton.2012.138.
[8] L. Zhu, A. Wang, J. Wang, Free-Space Data-Carrying Bendable Light Communications, Scientific Report, No. 9, 2019, pp. 14969, https://doi.org/10.1038/s41598-019-51496-z.
[9] S. Syubaev, A. Zhizhchenko, A. Kuchmizhak, A. Porfirev, E. Pustovalov, O. Vitrik, Yu. Kulchin, S. Khonina, S. Kudryashov, Direct Laser Printing of Chiral Plasmonic Nanojets by Vortex Beams, Journal of Physics: Conference Series, Vol. 951, 2018, pp. 012025, https://doi.org/10.1088/1742-6596/951/1/012025.
[10] Y. Zhang, M. Agnew, T. Roger, F.S. Roux, T. Konrad, D. Faccio, J. Leach, A. Forbes, Simultaneous Entanglement Swapping of Multiple Orbital Angular Momentum States of Light, Nature Communications, No. 8, 2017, pp. 632, https://doi.org/10.1038/s41467-017-00706-1.
[11] H. Y. Tsai, H. I. Smith, R. Menon, Fabrication of Spiral-Phase Diffractive Elements Using Scanning-Electron-Beam Lithography, Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures,
No. 25, 2007, pp. 2068-2071, https://doi.org/10.1116/1.2806961.
[12] T. Jankowski, N. Bennis, P. Morawiak, D. C. Zografopoulos, A. Pakuła, M. Filipiak, M. Słowikowski, J. M. López. Higuera, J. F. Algorri, Optical Vortices by An Adaptive Spiral Phase Plate, Optics & Laser Technology, Vol. 176, 2024, pp. 111029, https://doi.org/10.1016/J.OPTLASTEC.2024.111029.
[13] Y. H. Kim, C. Y. Hwang, J. H. Choi, J. E. Pi, J. H. Yang, S. M. Cho, S. H. Cheon, G. H. Kim, K. Choi, H. O. Kim, W. J. Lee, H. B. Kang, C. S. Hwang, Development of High-Resolution Active Matrix Spatial Light Modulator, Optical Engineering, Vol. 57, No. 6, 2018, pp. 1, https://doi.org/10.1117/1.oe.57.6.061606.
[14] A. S. Ostrovsky, C. R. Parrao, V. Arrizón, Generation of the Perfect Optical Vortex Using A Liquid-Crystal Spatial Light Modulator, Optics Letters, Vol. 38, Issue 4, 2013, pp. 534-536, https://doi.org/10.1364/ol.38.000534.
[15] K. Qu, Q. Jia, N.J. Fisch, Plasma Q-Plate for Generation and Manipulation of Intense Optical Vortices, Physical Review E, Vol. 96, No. 5, 2017, pp. 053207, https://doi.org/10.1103/PhysRevE.96.053207.
[16] D. W. Prather, J. N. Mait, M. S. Mirotznik, Design of Binary Subwavelength Diffractive Lenses by Use of Zeroth-Order Effective-Medium Theory, Journal of the Optical Society of America A, Vol. 16, Issue 5, 1999,
pp. 1157-1167, https://doi.org/10.1364/JOSAA.16.001157.
[17] A. Filipkowski, Fabrication and Integration of Nanostructured Optical Devices, Engineering and Physical Sciences, 2015, http://hdl.handle.net/10399/4073 (accessed on: July 30th, 2025).
[18] K. Switkowski, A. Anuszkiewicz, A. Filipkowski, D. Pysz, R. Stepien, W. Krolikowski, R. Buczynski, Formation of Optical Vortices with All-Glass Nanostructured Gradient Index Masks, Optics Express, Vol. 25, No. 25, 2017, pp. 31443, https://doi.org/10.1364/oe.25.031443.
[19] F. Hudelist, J. M. Nowosielski, R. Buczynski, A. J. Waddie, M. R. Taghizadeh, Nanostructured Elliptical Gradient-Index Microlenses, Optics Letters, Vol. 35, Issue 2, 2010, pp. 130-132, https://doi.org/10.1364/ol.35.000130.
[20] R. Kasztelanic, N. T. Hue, D. Pysz, H. Thienpont, T. Omatsu, R. Buczynski, Free-Form Optical Fiber with A Square Mode and Top-Hat Intensity Distribution, Advanced Science, Vol. 11, Issue 33, 2024, pp. 2402886, https://doi.org/10.1002/advs.202402886.
[21] N. T. Hue, K. Switkowski, R. Kasztelanic, A. Anuszkiewicz, Optical Characterization of Single Nanostructured Gradient Index Vortex Phase Masks Fabricated by the Modified Stack-And-Draw Technique, Optics Communications, Vol. 463, 2020, pp. 125435, https://doi.org/10.1016/j.optcom.2020.125435.
[22] N. T. Hue, L. V. Bau, C. V. Bien, T. T. Hai. L.V. Hieu, R. Kasztelanic, R. Buczynski, Achromatic Nanostructured Phase Components for Micro-Optical Vortex Beam Generation, Journal of the Optical Society of America B,
Vol. 42, Issue 6, 2025, pp. 1194-1203, https://doi.org/10.1364/JOSAB.555732.
[23] CDGM, (n.d.). https://www.cdgmgd.com//database/toWebDatabase.htm?k=Products_Data&url=database (accessed on: July 30th, 2025).
[24] F. Hudelist, R. Buczynski, A. J. Waddie, M.R. Taghizadeh, Design and Fabrication of Nano-Structured Gradient Index Microlenses, Optics Express, Vol. 17, No. 5, 2009, pp. 3255-3263, https://doi.org/10.1364/oe.17.003255.
[25] R. Buczynski, A. Filipkowski, B. Piechal, N. T. Hue, D. Pysz, R. Stepien, A. Waddie, M.R. Taghizadeh, M. Klimczak, R. Kasztelanic, Achromatic Nanostructured Gradient Index Microlenses, Optics Express, Vol. 27, No. 7, 2019, pp. 9588, https://doi.org/10.1364/oe.27.009588.
[26] N. T. Hue, R. Kasztelanic, A. Filipkowski, D. Pysz, L.V. Hieu, R. Stepien, T. Omatsu, W. Krolikowski, R. Buczynski, Broadband Optical Vortex Beam Generation Using Flat-Surface Nanostructured Gradient Index Vortex Phase Masks, Scientific Reports, No. 13, 2023, pp. 20255, https://doi.org/10.1038/s41598-023-46871-w.
[27] K. Okamoto, Fundamentals of Optical Waveguides, Academic Press, 2006, pp. 329-383.