The role of nanoscale etched Si surface in ZnO growth by continuous spray pyrolysis

This work reports deposition of various ZnO nanostructure layers by continuous spray pyrolysis reactor over seed layer assisted nanoscale etched Si surface. The study of various surface morphologies of ZnO nanostructure layers are supported by XRD, SEM, photoluminescence and reflectance measurements. The anisotropic etch pits surface energy profile has played an important role in deciding the ultimate surface morphology of ZnO film and may be helpful in generating vertically aligned ZnO nanorods. The 4 min etched Si surface show poor film quality which further improves with Si etching to 8 min. The 8 min etched Si is helping in ZnO growth and with the increase of deposition time shape, size and alignment of ZnO nanorods takes place. XRD pattern show fall of texture coefficient in ZnO growth with deposition time but it remains constant for 8 min etched Si. Photoluminescence study reveals presence of novel defect at 600 nm due to the Si etching and appreciable PL quenching is observed in ZnO growth for 8 min etched Si. Reflectance measurement show light reduction up to 40 and 47 % of existing reflectance in 400–800 nm wavelength regions due to the ZnO growth on 8 min and complete textured Si surface. The growth mechanisms for various ZnO growths are also proposed.