title: Dimensional Tailoring of Hydrothermally Grown Zinc Oxide Nanowire Arrays.
abstract: Hydrothermally synthesized ZnO nanowire arrays are critical components in a range of nanostructured semiconductor devices. The device performance is governed by relevant nanowire morphological parameters that cannot be fully controlled during bulk hydrothermal synthesis due to its transient nature. Here, we maintain homeostatic zinc concentration, pH, and temperature by employing continuous flow synthesis and demonstrate independent tailoring of nanowire array dimensions including areal density, length, and diameter on device-relevant length scales. By applying diffusion/reaction-limited analysis, we separate the effect of local diffusive transport from the c-plane surface reaction rate and identify direct incorporation as the c-plane growth mechanism. Our analysis defines guidelines for precise and independent control of the nanowire length and diameter by operating in rate-limiting regimes. We validate its utility by using surface adsorbents that limit reaction rate to obtain spatially uniform vertical growth rates across a patterned substrate.
authors.affiliation: Department of Materials Science and Engineering and ‡Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
authors.forename: Jayce J
authors.initials: JJ
authors.lastname: Cheng
authors.affiliation: Department of Materials Science and Engineering and ‡Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Nicaise
authors.affiliation: Department of Materials Science and Engineering and ‡Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
authors.forename: Karl K
authors.initials: KK
authors.lastname: Berggren
authors.affiliation: Department of Materials Science and Engineering and ‡Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
authors.forename: Silvija
authors.initials: S
authors.lastname: Gradečak
keywords: Zinc oxide; hydrothermal growth; morphological tailoring; nanowire density control; nanowires; reaction-limited growth