Broadband photodetection using one-step CVD-fabricated MoS2/MoO2 microflower/microfiber heterostructures
Résumé
Abstract Molybdenum disulfide (MoS 2 ) has been combined so far with other photodetecting semiconductors as an enhancing agent owing to its optical and electronic properties. Existing approaches demonstrated MoS 2 -incorporated photodetector devices using complex and costly fabrication processes. Here, we report on simplified one-step on the chemical vapor deposition (CVD) based synthesis of a unique microfiber/microflower MoS 2 -based heterostructure formed by capturing MoO 2 intermediate material during the CVD process. This particular morphology engenders a material chemical and electronic interplay exalting the heterostructure absorption up to ~ 98% over a large spectral range between 200 and 1500 nm. An arsenal of characterization methods were used to elucidate the properties of these novel heterostructures including Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectrometry, high-resolution transmission and scanning electron microscopies, and Kelvin probe force microscopy. Our findings revealed that the MoS 2 and the MoO 2 crystallize in the hexagonal and monoclinic lattices, respectively. The integration of the MoS 2 /MoO 2 heterostructures into functional photodetectors revealed a strong photoresponse under both standard sun illumination AM1.5G and blue light excitation at 450 nm. Responsivity and detectivity values as high as 0.75 mA W −1 and 1.45 × 10 7 Jones, respectively, were obtained with the lowest light intensity of 20 mW cm −2 at only 1 V bias. These results demonstrate the high performances achieved by the unique MoS 2 /MoO 2 heterostructure for broadband light harvesting and pave the way for their adoption in photodetection applications.