Controlling the diameter distribution and density of InAs nanowires grown by Au-assisted methods

Abstract

III-V semiconductor nanowires have attracted intensive research interest because of their promising optical and electronic properties that can be manipulated by tailoring nanowire composition and morphology. Therefore, it is crucial to measure and control the diameter distribution of the grown nanowires. In this study, we analyze the diameter distribution of Au-catalyzed InAs nanowires. Au colloidal nanoparticles dispersed on InAs (111) B substrates and nanoparticles obtained by the thermal annealing of Au films were used as catalysts for InAs nanowire growth. The annealing time and temperature, the thickness of the Au film and the colloid sizes were systematically varied not only to understand their influence on nanowire diameter distribution, but also to find the optimal parameters for realizing samples with uniform and controlled diameter distribution. Morphological characterization was performed by scanning electron microscopy measurements and the image analysis was carried out using in-house-developed automated image analysis software to accurately determine the diameter distribution of the nanowires. A description of the image analysis software is also presented. The thermal annealing of films turned out to be the most suitable method for uniformity and density control, while the colloidal nanoparticles yielded narrow and more reproducible diameter distributions.