A typical AFM image for Ge surface.
Chengzhao Chen, Cheng Li, Shihao Huang, Yuanyu Zheng, Hongkai Lai, Songyan Chen
CC BY 4.0
Chengzhao Chen et. al. "Epitaxial Growth of Germanium on Silicon for Light Emitters", International Journal of Photoenergy <a rel="nofollow" class="external text" href="https://doi.org/10.1155/2012/768605">doi:10.1155/2012/768605</a>