Hongxiang Zhang,Chunxia Wu,Canran Zhang,Bisheng Yan,Jiyuan Guo,Gangyi Zhu,Jun Dai
In this paper, we report the dual-wavelength green-light emission from zinc oxide (ZnO)-nanoseed-decorated p-GaN (gallium nitride)/n-ZnO nanorod/CsPbBr3 quantum dots (QDs) light-emitting diodes (LEDs). At the same time, the effect of ZnO nanoseeds on the p-GaN/n-ZnO nanorod/CsPbBr3 QDs LED performance is deeply studied. ZnO nanoseeds were fabricated by magnetron sputtering and the sol–gel method; then ZnO nanorods were obtained on GaN by hydrothermal treatment to form the p-GaN/n-ZnO nanorod heterojunction, and green CsPbBr3 QDs were further deposited on ZnO nanorod arrays to realize LEDs. The results show that magnetron-sputtering ZnO nanoseeds can induce regular vertical ZnO nanorod arrays, and the corresponding device presents a better electroluminescence (EL) performance. The X-ray diffraction, atomic force microscopy, and EL mechanisms indicate that the p-GaN/n-ZnO nanorod with magnetron-sputtering ZnO nanoseeds has a better crystalline interface. Our results indicate that the p-GaN/n-ZnO nanorod/CsPbBr3 QDs heterojunction structure can be served as dual-wavelength LEDs, and magnetron-sputtering ZnO nanoseeds can give rise to a better EL performance.
Cen Zhang,Xiaonan Zhu,Fei Gao,Liu Yang,Weizhen Liu
The development of wavelength adjustable electrically driven panchromatic display light-emitting devices (LEDs), a future direction for lighting sources, still seems necessary because of great development prospects and practical significance. Herein, perovskite quantum dots (QDs) of CsPbBr 3 and CsPbI 3 with multi-color luminescence feature were employed into n-ZnO/p-GaN nano-heterojunction LEDs. A thin polystyrene cover layer was intentionally inserted between CsPbBr 3 and CsPbI 3 to prevent the undesired halogen anion-exchange reaction. A color-tunable electroluminescence (EL) could be achieved by changing the molar ratio of these two types of perovskite QDs. By further optimizing the molar ratio between CsPbBr 3 and CsPbI 3 , that is, the evolution of the share of red, green and blue-violet luminescence in EL spectra, a stable white light emission was obtained. The current research not only achieves multi-color EL emissions in a three-dimensional nano-architecture, but also proposes an effective and clever strategy for preparing and developing single-chip white LEDs.
Heterojunction phototransistor (HPT) is considered the most promising detector technology in weak ultraviolet (UV) signal detection due to its inherent internal gain through transistor action. However, achieving high-performance self-powered UV HPTs remains a significant challenge. In this study, a high-performance self-powered p + -GaN/n − -ZnO/Au UV HPT with ZnO serving as the floating base is cleverly designed. The device features a unique back-to-back configuration of the p + -GaN/n − -ZnO heterojunction and n − -ZnO/Au Schottky junction, along with an ultrathin ZnO base layer of a 3D nanowire network structure. This design enables the fabricated p + -GaN/n − -ZnO/Au UV HPT to operate in a self-powered mode with exceptional performance metrics. Under zero bias, the device exhibits outstanding characteristics including ultralow dark current of 1.7 × 10 −13 A, remarkable I photo /I dark ratio of 10 6 , fast response speed (t r = 150 µs / t f = 250 µs), high responsivity of 9.74 A W −1 , and detectivity of 1.58 × 10 14 Jones, representing the best result achieved for UV HPTs thus far at zero bias. Moreover, the fabricated UV HPT is successfully demonstrated in solar-blind imaging and UV communication systems without the need for an external power supply. This work presents effective and practical design strategies for achieving high-performance self-powered UV HPTs.
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