Boosting the performance of ZnO microrod metal-semiconductor-metal photodetectors via surface capping of thin amorphous Al₂O₃ shell layer

Abstract

1D ZnO nanostructures have been widely explored due to their potential applications in ultraviolet (UV) region photodetectors because of their unique structural and optoelectronic properties. However, a large number of surface defect states leading to a noticeable dark current hinders their practical applications in UV photodetection. In this work, we have shown improved ZnO/Al 2 O 3 core-shell microrod photodetectors, whose performance is significantly enhanced by defect passivation and the introduction of trap states by atomic layer deposition grown thin amorphous Al 2 O 3 shell layer, as evidenced by steady-state and transient photoluminescence investigations. The photodetectors demonstrated suppressed dark current and increased photocurrent after capping the Al 2 O 3 layer. Specifically, the ZnO/Al 2 O 3 core-shell microrod photodetector exhibited a photoresponsivity as high as 0.019 A/(W cm −2 ) with the dark current as low as ~1 × 10 −11 A, and a high I light /I dark ratio of ~10 4 under relatively weak light illumination (~10 µW cm −2 ). The results presented in this work provide valuable pathways to boost the performance of 1D ZnO microrod-based photodetectors for future practical applications.

Improved CsPbBr3 visible light photodetectors via decoration of sputtered au nanoparticles with synergistic benefits

“…One possible explanation is the formation of trap states at the surface, which was commonly observed in the ZnO‐based UV PD devices. [ 58,59 ] However, such an opinion is not supported by the time‐resolved photocurrent (Figure 3D) and RT steady‐state PL results (Figure 5B). We anticipate that the sputtered Au NPs have little impact on the surface of CsPbBr 3 due to the very low sputtering power (2 W).…”

“…If not so, the response speed will be lowered due to the typical charge carriers trapping and de‐trapping process. [ 58,59 ] Meanwhile, as the nonradiative recombination centers, trap states will further deteriorate the RT PL performance. [ 60 ] As a result, it is reasonably suggested that the enhanced photocurrent and photo sensitivity in the Au@CsPbBr 3 PD shown in Figures 3A, B, and C originate from the localized Schottky junction formed at the Au NPs/CsPbBr 3 interface, as shown in Figure 4D.…”

High Responsivity and EQE of Single ZnO:Sb Microwire/Ti3C2Tx Heterojunction UV Photodetector

“…Therefore, strategies for surface modifying will be effective ways to enhance the performance of 1D MW-based PD devices by tuning the charge traps and nonradiative centers. 19 Meanwhile, the core− shell heterojunction can not only take full advantage of different functional materials but also induce novel properties owing to the particular characteristics of the junction. 20 significance in terms of surface modification and the alignment of the energy level configuration.…”

Improved Working Temperature and Capacitive Energy Density of Biaxially Oriented Polypropylene Films with Alumina Coating Layers

“…Alumina (Al 2 O 3 ) is a well-known insulator that possesses good thermal, mechanical, and chemical stability, and it has a relatively high permittivity (ε r ∼ 9.0), high thermal conductivity (∼2–30 W/(m·K)), − wide band gap (∼7.0 eV), and high Young’s modulus (∼100 GPa) . These properties make Al 2 O 3 a promising material to enhance the capacitive energy-storage performances of polymer-based dielectrics. ,, Al 2 O 3 has been used as nanofillers to improve the room-temperature performances of PP , and as coating layers to improve the performances of polyimide .…”

“…In principle, coating a material with a higher dielectric constant would improve the energy storage more obviously. Alumina (Al 2 O 3 ) is a well-known insulator that possesses good thermal, mechanical, and chemical stability, 26 and it has a relatively high permittivity (ε r ∼ 9.0), 27 high thermal conductivity (∼2−30 W/(m•K)), 28−30 wide band gap (∼7.0 eV), 31 and high Young's modulus (∼100 GPa). 32 These properties make Al 2 O 3 a promising material to enhance the capacitive energy-storage performances of polymer-based dielectrics.…”