Monolayer MoS₂ on Paper with a Copper Electrode: An Integrated CVD-Grown Broadband UV-Visible Photodetector

The commercial viability of flexible and disposable photodetectors is often constrained by the reliance on costly noble-metal electrodes and conventional substrates. Here, we address these challenges by integrating a chemical vapor deposition (CVD)-grown monolayer MoS₂ with a low-cost copper (Cu) electrode on a paper substrate, combining scalable semiconductor synthesis with inexpensive device components. Raman, photoluminescence, and X-ray photoelectron spectroscopy measurements confirmed the crystallinity of the MoS₂ monolayer and its direct bandgap of 1.8 eV. The fabricated device demonstrated a broadband photoresponse covering the ultraviolet and visible regions, achieving a maximum responsivity and specific detectivity of 1.37 mA/W and 3.17 × 10⁹ Jones, respectively, at 320 nm under 5 V bias and an incident power density of 2.14 mW/cm². The device retains a well-resolved photoresponse under bending to a radius of 11.25 mm and over 100 bending cycles, confirming the mechanical robustness of the paper platform. By replacing the noble-metal contacts with low-cost Cu electrodes and conventional polymer substrates with paper while employing scalable CVD-grown MoS₂, this work establishes an economically viable platform for the large-scale manufacture of flexible and disposable photodetectors while providing a scalable pathway toward their large-area manufacture.