Effects of various seed layers on the agglomeration phenomenon on a MgO substrate

In this study, samples composed of various materials were fabricated using direct current magnetron sputtering on a single-crystal MgO(001) substrate. Ti, Cr, and Co were used as the seed layers, and Ag was used as the upper layer. Atomic force microscopy confirmed that Ag nanodots with regular shapes were formed when Ti was used as a seed layer, but when other materials were used, irregularly shaped nanodots were formed. Furthermore, it was confirmed that thermal agglomeration was disrupted if the thickness exceeded the critical point. Moreover, X-ray diffraction analysis indicated that the use of Ti in the seed layer promoted the epitaxial growth of Ag nanodots along the plane of the MgO(001) substrate; in contrast, Ag/Cr nanodots grew non-epitaxially. Based on the results of this study, it can be concluded that Ti is the most suitable seed layer material for Ag nanodot formation among the three materials examined herein.