Two-dimensional growth of germanium under a diffusion limited aggregation environment

The discovery of graphene has triggered immense interest in two-dimensional (2D) nanomaterials. However, the 2D growth of several layerstructured crystals such as graphene, MoS₂, and black phosphorus is difficult and limited. Here, we report the gas-phase 2D growth of germanium (Ge) with a cubic structure to form Ge nanosheets (GeNSs) using the chemical vapor deposition method. Our investigation revealed that a diffusion limited aggregation (DLA) environment is essential for the 2D growth of Ge that induces a dendritic growth in the <110> direction and suppresses the growth in the [111] direction. The growth behavior was similar to the 2D growth of silicon reported previously. Thus, it can be concluded that a DLA environment is essential for the 2D growth of cubic structured materials. The electron density and mobility of GeNSs were found to be 1.3 × 10¹⁵ cm⁻³ and 792 cm²/Vs, respectively, and their resistivity varied with the intensity of light. [Figure not available: see fulltext.]