Highly Air-Stable and Sensitive Self-Powered Broadband Photodetector Based on a PVA–MoS₂ Fibers/n-Si Heterojunction

We designed and demonstrated a self-powered poly(vinyl alcohol) (PVA)–MoS2 fibers/n-Si heterojunction (HJ) device for a high-performance photodetector. Light-intensity-dependent I–V measurements were carried out, ranging from the dark to 150 mW/cm2 for visible light. Furthermore, electro-optical measurements of HJ under UV (365 and 395 nm), IR (850 nm), and yellow light (590 nm) for constant light power were investigated in detail with the help of I–V characteristics. The PVA–MoS2/n-Si device showed a pronounced photoresponse at all of these wavelengths. The optimum values of the wavelength-dependent photodetector parameters were obtained under yellow light. In the evaluation of the optical measurements under yellow light, the maximum on/off ratio, R, D, NPDR, and EQE values were 2.91 × 105 (zero bias), ∼480 mA/W (V = −2.0 V), 5.71 × 1012 Jones (zero bias), 4.64 × 109 W1– (zero bias), and 100.8 (V = −2.0 V), respectively. Furthermore, after 25 and 125 days without any encapsulation, the air stability of the device was observed to be excellent in the dark and the light.