Growth of aluminum oxide nanorods using sandwich structures composed of Al and SiOx layers

In this work, we report a simple method for growing aluminum oxide nanorods based on low-temperature annealing of a sandwich structure composed of a thin Al film sandwiched between two silicon-rich oxide (SiOx: 0 < x < 2) layers produced by plasma-enhanced chemical vapor deposition. Aluminum oxide nanorods produced using a typical sandwich structure of SiO1.4(20 nm)/Al(2 nm)/SiO1.4(20 nm)/Si substrate exhibited the features of the mean diameter and length of the nanorods of about 0.3 and 1.7 μm, respectively. A possible growth mechanism is discussed on the basis of the vapor–solid process. The nanorod growth is proposed to be mediated by a vapor–solid mechanism in which the dominant vapor-phase source of reactants is Al2O/AlO produced by a phase separation of SiOx.