A template-free CVD route to synthesize hierarchical porous ZnO films. (December 2015)

• Record Type: Journal Article
• Authors: Duan, Xiangyang; Chen, Guangde; Guo, Lu'an; Zhu, Youzhang; Ye, Honggang; Wu, Yelong
• Is Part Of: Superlattices and microstructures. Volume 88(2015)
• Page Start: 501
• Page End: 507
• Publication Date: 2015-12
• Subjects: ZnO -- Porous film -- Seed layer -- Chemical vapor deposition; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2015.10.010
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: Unique porous ZnO films were successfully synthesized on Si substrates without any catalysts or templates using chemical vapor deposition method. Unlike earlier reports, they are hierarchical porous, containing both macropores and mesopores. The zinc oxide seed layer and the weight ratio of source materials were found to be the major factors that would facilitate the synthesis of these hierarchical porous films. We found that all the macropores were surrounded by grain boundaries. As presented in the SEM images, the newborn ZnO atoms would prefer to adsorb nearby the grain boundaries and nucleate there in the growth stage. A schematic diagram based on the aforesaid phenomenon was proposed to explain the synthesis of the hierarchical porous ZnO film. An unusual strong emission peak located at 420 nm was observed in the photoluminescence spectrum. It was suggested that the emission peak was attributed to the special hierarchical porous structure, especially the grain boundaries in the nanowalls of these films. Highlights: Using CVD method, unique porous ZnO films were synthesized on Si substrate without any catalyst or template. These films are hierarchical porous, containing both macropores and mesopores. A growth mechanism is proposed, and the seed layer and the weight ratio of the source materials are major factors. An unusual strong emission peak located at 420 nm was observed in the photoluminescence spectrum.