ZnO/CuCrO₂ Core–Shell Nanowire Heterostructures for Self‐Powered UV Photodetectors with Fast Response

Abstract

An original self-powered UV photodetector integrating ZnO/CuCrO 2 core-shell nanowire heterostructures is fabricated using low-cost and scalable chemical deposition techniques operating at moderate temperatures. A 35 nm thick delafossite phase CuCrO 2 shell is formed with high uniformity by aerosol-assisted chemical vapor deposition over an array of vertically aligned ZnO nanowires grown by chemical bath deposition. The CuCrO 2 shell consists of columnar grains at the top of ZnO nanowires as well as nanograins with some preferential orientations on their vertical sidewalls. The ZnO/CuCrO 2 core-shell nanowire heterostructures exhibit significant diode behavior, with a rectification ratio approaching 1.2 × 10 4 at 1 V and -1 V, as well as a high optical absorptance above 85% in the UV part of the electromagnetic spectrum. A high UV responsivity at zero bias under low-power illumination of up to 3.43 mA W -1 under a 365 nm UV lamp, and up to 5.87 mA W -1 at 395 nm from spectrally resolved measurements, alongside a high selectivity with a UV-to-visible (395-550 nm) rejection ratio of 106 is measured. The short rise and decay times of 32 and 35 µs, respectively, both measured at zero bias, further establish these devices as promising candidates for cost-efficient, all-oxide self-powered UV photodetectors.

Compositional and structural engineering of inorganic nanowires toward advanced properties and applications

“…1D core‐shell heterojunction nanostructures have great potential for high‐performance compact optoelectronic devices owing to their high interface area‐to‐volume ratio . To date, core‐shell heterostructure nanowire systems, such as InAs/AlSb, InGaAs‐GaAs, ZnO/CuCrO 2 , and GaN/AlN, with outstanding performance as photodetectors have been reported . For example, β‐Ga 2 O 3 is an excellent candidate for solar‐blind photodetection, with a direct wide bandgap of ~ 4.9 eV (253 nm).…”

“…152 To date, core-shell heterostructure nanowire systems, such as InAs/AlSb, InGaAs-GaAs, ZnO/CuCrO 2 , and GaN/AlN, with outstanding performance as photodetectors have been reported. [153][154][155][156] For example, β-Ga 2 O 3 is an excellent candidate for solarblind photodetection, with a direct wide bandgap of 4.9 eV (253 nm). Most β-Ga 2 O 3 nanostructure-based photodetectors are photoconductive with a relatively slow response speed due to the persistent photoconductivity effect.…”

Ultrahigh Responsivity UV Photodetector Based on Cu Nanostructure/ZnO QD Hybrid Architectures

“…To boost the performance, a common and feasible approach is synthesis of low‐dimensional ZnO nanostructures (NSs) to trap the incident light beams, such as ZnO nanowires (NWs), nanoflowers, and nanoflakes, which can significantly restrict the response speed and carrier transport of devices. Alternatively, another effective approach is combining other materials to fabricate p‐n junctions working at a relatively lower voltage, such as 3,4‐ethylenedioxythiophene: poly(styrenesulfonate) (PEDOT:PSS), CuS, CuCrO 2 , NiO, etc., but it can sacrifice the commercial costs against the Moore's law of miniaturization of microelectronics and introduce mismatch in detectors.…”

Ultrahigh‐Performance Self‐Powered Flexible Photodetector Driven from Photogating, Piezo‐Phototronic, and Ferroelectric Effects

“…Heterojunction photodetectors can also be constructed using a hybrid junction of organic and inorganic materials, which provide benefits such as low materials synthesis and junction fabrication cost. Nevertheless, lattice mismatch between different materials results in crystalline defects and causes low photocurrent and responsivity, which consequently have posed a challenge for high‐performance heterojunction self‐powered photodetectors …”