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The self-powered PVP-Co@C nanofibers/n-GaAs heterojunction photodetector (HJPD) was fabricated by electrospinning of the nanofibers onto GaAs. An excellent rectification ratio of 6.60 × 106 was obtained from I – V measurements of the device in the dark. The I – V measurements of the fabricated device under 365 nm, 395 nm and 850 nm lights, as well as I – V measurements in visible light depending on the light intensity, were performed. The HJPD demonstrated excellent photodetection performance in terms of a good responsivity of ∼225 mA W−1 (at −1.72 V) and at zero bias, an impressive detectivity of 6.28 × 1012 Jones, and a high on/off ratio of 8.38 × 105, all at 365 nm wavelength. In addition, the maximum external quantum efficiency and NPDR values were 3495% (V = −1.72 V) and 2.60 × 1010 W−1 (V = 0.0 V), respectively, while the minimum NEP value was ∼10−14 W.Hz−1/2 for 365 nm at V = 0.V volts. The HJPD also exhibited good long-term stability in air after 30 d without any encapsulation. [ABSTRACT FROM AUTHOR]

Mn:CeO2/PVP nanofibers were prepared via a simple electrospinning technique with heat treatment at 500°C. X-ray diffraction patterns revealed the formation of a face-centered cubic structure for pure and Mn:CeO2 nanofibers. Whole powder pattern modeling was applied to the x-ray diffraction data for pure and Mn:CeO2 nanofibers to determine the microstructure parameters (the crystalline domain size and the size distribution). The effect of Mn doping on the morphology features of the prepared nanofibers was assessed from the scanning electron microscopy (SEM) image analysis. The SEM images showed random fibers with no distinct alignment, with average fiber diameters of about 80–150 nm after calcination. FT-IR spectra of the Mn0.05Ce0.95O2 nanofibers showed stretching vibrations corresponding to Mn-O and Ce-O bonds. The optical absorption of pure and Mn:CeO2 nanofibers was studied using diffuse reflectance spectroscopy. The optical band gap was found to increase with increased Mn doping, which can be attributed to the quantum confinement effect. [ABSTRACT FROM AUTHOR]