Although vapor-liquid-solid (VLS) growth has become a standard method for producing nanowires, the underlying growth mechanisms have not been fully elucidated because VLS growth is affected by thermodynamic and geometrical factors that, to date, have mainly been considered separately. Based on the assumption that the irregular nanowire growth reflects the conditions of the eutectic droplet during nanowire growth, we aimed to elucidate the thermodynamic and geometrical aspects of the growth mechanisms by the measurement and analysis of irregular kinked and curved Si nanowires grown by Au-catalyzed VLS. The results suggest that kinked nanowires may be caused by higher supersaturation, whereas curved nanowires may be caused by lower supersaturation within the eutectic Au-Si droplet. The results of measuring and analyzing irregular nanowires confirmed that both thermodynamic and geometrical effects complexly influence nanowire growth kinetics, particularly the supersaturation of eutectic droplets, and the effects are more pronounced in larger diameter nanowires. (C) 2014 Elsevier B.V. All rights reserved.