Multilayer calculation on SR signal during growth of ZnO nanorod

The growth procedure of ZnO nanorods was monitored by in-situ spectral reflectance (SR) method. The ZnO nanorods were grown on both Si and sapphire substrates by using catalyst-free, low-pressure metalorganic chemical vapor deposition. We observed that the SR signals at all wavelengths changed by the same amount at the first stage of ZnO growth and then followed different trajectories for different wavelengths. Distortion of the SR oscillation was observed, which was interpreted to indicate the starting point of the growth of nanorods. To confirm the analysis, we compared the measured SR signal with the SR response calculated by using multilayer model.