Controllable Heterogeneous Nucleation for Patterning High‐Quality Vertical and Horizontal ZnO Microstructures toward Photodetectors

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 16; no. 42
• Main Authors: Li, Haohao, Liu, Meilin, Zhao, Jinjin, Gao, Hanfei, Feng, Jiangang, Jiang, Lei, Wu, Yuchen
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.10.2020
• Subjects: Arrays; Crystallization; Crystallography; Drying; heterogeneous nucleation; high‐quality crystal arrays; Hydrothermal crystal growth; microstructures; Nanocrystals; Nanostructure; Nanotechnology; Nucleation; Optimization; Optoelectronics; photodetectors; Photometers; Polydimethylsiloxane; Precursors; Recyclability; Stability; Substrates; Zinc oxide; Zinc oxides
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202004136

High‐quality crystalline micro‐ and nanostructures based on inorganic semiconductors including zinc oxide (ZnO) have attracted considerable interest in electronic and optoelectronic applications due to their outstanding properties. ZnO micro‐ and nanocrystals can be fabricated by the moderate and high throughput hydrothermal synthesis. Yet it is restricted by patterning large‐area ZnO crystals with high‐quality and programmable geometries through the hydrothermal process for the optoelectronic integration. Here, a capillary‐bridge manipulation approach is demonstrated to control the dewetting process of ZnO precursor solution for patterning precursor arrays. Based on precursor arrays, vertically aligned high‐quality ZnO microrod arrays with homogeneous morphology and pure crystallographic orientation are fabricated via a hydrothermal epitaxial method. Statistical results and crystallization theories guide the experimental optimization and discussion of the crystallization mechanism, dominated by the competition between homogeneous nucleation and heterogeneous nucleation. High‐quality ZnO microbelt arrays are achieved through a surfactant‐mediated hydrothermal method after ZnO microrod arrays are transferred to a polydimethylsiloxane substrate. Photodetectors based on ZnO microbelts exhibit a high responsivity of 2.3 × 104 A W−1, a light on–off ratio exceeding 105, and stable recyclability. It is anticipated that this work provides new insights into patterning inorganic high‐quality micro‐ and nanostructures for multi‐functional integrated devices. High‐quality ZnO crystal microrod and microbelt arrays with precise arrangement and pure crystallographic orientation are fabricated by the combination of the capillary‐bridge lithography method and hydrothermal method. The discussion of crystallization mechanism is performed through the competition between homogeneous and heterogeneous nucleation processes. Photodetectors based on microbelt arrays exhibit high optoelectronic performance owing to the smooth surface energy band.