The controllability of persistent photoconductance （PPC） and charge/energy storage of ZnO nanorod arrays （NRAs） were demonstrated experimentally by tuning the nanorod diameter. The dependency of the ZnO NRAs＇ pho...The controllability of persistent photoconductance （PPC） and charge/energy storage of ZnO nanorod arrays （NRAs） were demonstrated experimentally by tuning the nanorod diameter. The dependency of the ZnO NRAs＇ photoelectric characteristics on the nanorod diameter suggests that the Debye length and photon penetration depth in ZnO could spatially partition a standalone nanorod into three different photoelectric functional regions （PFRs）. Theoretically, a series of rate functions was employed to describe the different extrinsic/intrinsic carrier photogeneration/recombination dynamic sub-processes occurring in the different PFRs, associated with oxygen chemisorption/photodesorption, oxygen vacancy photoionization, and electron trapping by photoionized oxygen vacancies. On the basis of the coupled contributions of these different dynamic sub-processes in the photoelectric properties of the ZnO NRAs, a thorough-process photoelectric dynamic model （TPDM） was proposed using the simultaneous rate functions. Through solving the rate functions, the corresponding analytical equations could be employed to simulate the time-resolved PPC spectra of the ZnO NRAs, and then the quantitative parameters extracted to decipher the PPC and charge/energy storage mechanisms in the ZnO NRAs. In this way, the TPDM model provided a numerical-analytical method to quantitatively evaluate the photoelectric properties of ZnO NRA-based devices. Additionally, the TPDM model revealed how the different photoinduced carrier dynamics in the different PFRs could play functional roles in different optoelectronic applications, e.g., photodetectors, photocatalysts, solar cells and optical nonvolatile memories, and thus it illuminated a practical approach for the design of ZnO NRA-based devices via optimization of the modularized spatial configuration of the PFRs.展开更多
基金This work was supported by National Natural Science Foundation of China （No. 50927201） and the National Basic Research Program of China （Nos. 2009CB939705 and 2009CB939702）. The authors are also grateful to Analytical and Testing Center of Huazhong University of Science and Technology.
文摘The controllability of persistent photoconductance （PPC） and charge/energy storage of ZnO nanorod arrays （NRAs） were demonstrated experimentally by tuning the nanorod diameter. The dependency of the ZnO NRAs＇ photoelectric characteristics on the nanorod diameter suggests that the Debye length and photon penetration depth in ZnO could spatially partition a standalone nanorod into three different photoelectric functional regions （PFRs）. Theoretically, a series of rate functions was employed to describe the different extrinsic/intrinsic carrier photogeneration/recombination dynamic sub-processes occurring in the different PFRs, associated with oxygen chemisorption/photodesorption, oxygen vacancy photoionization, and electron trapping by photoionized oxygen vacancies. On the basis of the coupled contributions of these different dynamic sub-processes in the photoelectric properties of the ZnO NRAs, a thorough-process photoelectric dynamic model （TPDM） was proposed using the simultaneous rate functions. Through solving the rate functions, the corresponding analytical equations could be employed to simulate the time-resolved PPC spectra of the ZnO NRAs, and then the quantitative parameters extracted to decipher the PPC and charge/energy storage mechanisms in the ZnO NRAs. In this way, the TPDM model provided a numerical-analytical method to quantitatively evaluate the photoelectric properties of ZnO NRA-based devices. Additionally, the TPDM model revealed how the different photoinduced carrier dynamics in the different PFRs could play functional roles in different optoelectronic applications, e.g., photodetectors, photocatalysts, solar cells and optical nonvolatile memories, and thus it illuminated a practical approach for the design of ZnO NRA-based devices via optimization of the modularized spatial configuration of the PFRs.
