Novel Ω‐Shaped Core–Shell Photodetector with High Ultraviolet Selectivity and Enhanced Responsivity

Abstract

The design of nanostructure plays an important role in performance enhancement of low-dimensional optoelectronic devices. Herein, a novel photodetector (PD) based on electrospun SnO 2 nanofibers with Ω-shaped ZnO shell (SnO 2 @ZnO) is fabricated. With 87.4% transmittance at 550 nm, SnO 2 @ZnO PD exhibits a high photo-to-dark current ratio up to 10 4 at around 280 nm. Owing to the additional Ω-shaped ZnO shell, SnO 2 @ZnO PD possesses a responsivity of nearly 100 A W −1 under 5 V bias and the illumination of 250 nm light, which is 30-time enhancement of pristine SnO 2 PD. The enhancement is mainly attributed to type-II energy band structure. Furthermore, by changing the direction of incident light, SnO 2 @ZnO PD has a high UV selectivity with an UV-vis rejection ratio (R 250 nm /R 400 nm ) as much as 2.0 × 10 3 at 5 V bias under back illumination, which is fourfold higher than that under face illumination. The UV selectivity improvement may be attributed to light confinement in the Ω-shaped structure. With both theoretical simulations and experimental comparisons, it is demonstrated that the unique compact Ω-shaped nanostructure does contribute to photon trapping and gaining process, especially in back-illumination configuration. The approach can be easily extended to other materials, preparing novel building blocks for optoelectronic devices.

Si/CuIn0.7Ga0.3Se2 Core–Shell Heterojunction for Sensitive and Self‐Driven UV–vis–NIR Broadband Photodetector

“…Notably, all of the five diffraction peaks are sharp, indicating its high crystallinity. The average grain size ( L ) of crystalline domains is calculated with the Scherrer equationwhere K is a sharp factor set as unity, λ is the X‐ray wavelength (0.1548 nm), and β (in radians) is the full width at half maximum at an angle 2θ. The size of crystalline domains L is estimated to be 98 nm based on the strongest peak of (112) facet.…”

Enhancing the Photoelectric Performance of Photodetectors Based on Metal Oxide Semiconductors by Charge‐Carrier Engineering

“…Recently, a Ω‐shaped 1D SnO 2 @ZnO PD with electrospun SnO 2 nanofibers as core and ultrathin ZnO film as shell has been reported. It exhibits a high photo‐to‐dark current ratio of up to 10 4 at around 280 nm . As demonstrated by both theoretical simulations and experimental comparisons, the unique compact Ω‐shaped nanostructure does contribute to photon trapping and gaining process, especially in the back‐illumination configuration.…”

Materials and Designs for Wearable Photodetectors

“…Photodetectors (PDs), which transform light into other signals, have been widely used in ozone sensing, flame detection, medical imaging, memristor, astronomical exploration, and so forth . The most commonly and widely used PDs are the photoelectrical detectors, which convert electromagnetic radiation into electrical currents, and so far high‐performance photodetectors have been fabricated based on that . The application of such devices on wearables utilizes the photodetection principles to meet the practical requirements and also provides opportunities for the realization of smart monitoring.…”