Concurrent Improvement of Photocarrier Separation and Extraction in ZnO Nanocrystal Ultraviolet Photodetectors

Abstract

Polycrystalline film photodetectors often suffer from several drawbacks, such as uncontrollable defect species, grain boundary scattering, and surface oxygen trapping/detrapping, hindering their practical applications in high-performance UV photodetection. In this work, we induce an acceptor-type zinc vacancy (VZn) defect in zero-dimensional ZnO nanocrystals by a dual thermal annealing process, which has been closely examined by a defect-sensitive electron paramagnetic resonance technique. The optimization of annealing parameters can well tune the VZn concentration and induce a considerable self-powered behavior, which is believed to result from ionized acceptor enhanced charge separation. On the other aspect, the capping of metallic Zn can lead to the formation of abundant interface conducting channels for the highly efficient charge transport and extraction. The optimized responsivity is enhanced from 5.3 × 10–3 to 15.3 A W–1, and the average rise and decay times remain at 36.6 and 101.8 ms, respectively. Conductive atomic force microscopy confirms a uniform photocurrent distribution in the annealed polycrystalline films, suggesting the significance of synergies of lattice defects and grain boundary conductive channels. This study unambiguously demonstrates a new route to engineer the photodetection in nanocrystalline oxides, providing a promising prospect for future low-cost, low-power-consumption micro-/nano-optoelectronic devices.

Antibiofouling Thin‐Film Nanocomposite Membranes for Sustainable Water Purification

“…Metal oxide nanoparticles (MeO NPs) are another type of nanoparticles that have received growing attention owing to their potential in several technological applications. [111][112][113][114] Metal elements can form a diverse range of oxide compounds such as nanowires, nanotubes, and nanospheres. The nanostructures formed by the MeO NPs provide an alternative strategy for effectively dealing with bacteria.…”

Crystallization of ZnO thin films without polymer substrate deformation via thermal dissipation annealing method for next generation wearable devices

“…12 In contrast, ZnO-based UV photodetectors are free from the requirement of complex lter due to their wide direct band gap of 3.37 eV and large exciton binding energy of 60 meV. [13][14][15] Additionally, ZnO is a suitable material for transparent and exible optoelectronics owing to its high electron mobility and high transparency in the visible region. To fabricate ZnO based UV photodetector, various deposition method, such as metal-organic chemical vapor deposition, molecular beam epitaxy (MBE), pulsed laser deposition, sol-gel spin-coating method, and hydrothermal method, have been used.…”

Self‐Powered and Broadband Photodetector Based on SnS2/ZnO1−xSx Heterojunction

“…[ 27–29 ] In addition, ZnO‐based PDs are endowed the advantages of low applied field, fast response, and no oxygen dependency. [ 30,31 ] On the other hand, the doping of S atom can not only improve the optical and electrical properties of ZnO, but also modify the band structure of ZnO resulting in the mitigation of the interfacial recombination. [ 32 ] As a result, ZnO 1− x S x can be a good candidate to construct heterojunction PDs.…”