Application of spectral reflectance to the monitoring of ZnO nanorod growth

By using spectral reflectance (SR), we report on the in situ monitoring of ZnO nanorod growth on Si and sapphire substrates by catalyst-free, low pressure metalorganic chemical vapor deposition. Initially, the SR signals showed the same behavior at various wavelengths but at some point they began to strongly interfere and oscillate. This is interpreted as the starting point of the growth of nanorods. Simulation results using a multilayer model confirmed our analysis.