Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Effects of substrate annealing on the goldcatalyzed growth of ZnO nanostructures | Weigand et al. Nanoscale Research Letters 2011 6 566 http content 6 1 566 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Effects of substrate annealing on the gold-catalyzed growth of ZnO nanostructures Christian C Weigand1 Daniel Skare2 Cecile Ladam3 Jostein Grepstad1 and Helge Weman1 Abstract The effects of thermal substrate pretreatment on the growth of Au-catalyzed ZnO nanostructures by pulsed laser deposition are investigated. C-plane sapphire substrates are annealed prior to deposition of a thin Au layer. Subsequent ZnO growths on substrates annealed above 1 200 C resulted in a high density of nanosheets and nanowires whereas lower temperatures led to low nanostructure densities. Separate Au film annealing experiments at 700 C showed little variation in the size and density of the Au catalyst droplets with substrate annealing temperature. The observed variation in the density of nanostructures is attributed to the number of surface nucleation sites on the substrate leading to a competition between nucleation promoted by the Au catalyst and surface nucleation sites on the rougher surfaces annealed below 1 200 C. Keywords zinc oxide laser ablation atomic force microscopy thermal annealing vapourliquid-solid growth nanostructures surface roughness surface defects Introduction Semiconductor nanostructures have attracted great interest in the past decade due to a wide range of potential applications . in solar cells lasers and sensors and as building blocks of integrated systems 1-3 . Fabrication of different types of nanostructures such as nanowires nanorods nanobelts and nanosheets can be achieved from a variety of methods including solution-based chemical and physical vapor deposition techniques with and without the use of a metal catalyst 1 4-7 . The morphology and orientation of nanostructures can be controlled by tuning growth parameters such as the substrate temperature background pressure and .
