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Description
Germanane is a group IV, two-dimensional semiconductor, analogous to graphane, which is predicted to possess a direct bandgap. Its structure and properties can be tuned by surface functionalization, which can also increase the material’s stability. Chemically synthesized crystals of methyl-terminated (GeCH₃) germanane are exfoliated via the scotch-tape method, and the resulting multilayered flakes are systematically investigated, focusing on their structural, chemical, thermal, and electrical characteristics. Raman spectroscopy and photoluminescence (PL) measurements reveal distinct vibrational modes characteristic of a germanium-based 2D material and emission features that confirm the presence of a direct band gap of approximately 1.75 eV.
XPS analysis shows the expected Ge signature, without indication of Germanium oxidation. Furthermore, the thermal stability of GeCH₃ was examined through annealing studies in N2 and forming gas atmospheres, demonstrating a stability up to 200 °C. To explore the electronic performance, back-gated metal–oxide–semiconductor field-effect transistor (MOSFET) devices were fabricated. Initial electrical characterization shows clear light-dependent conductivity. These findings indicate that methyl-terminated germanane is a promising candidate for the realization of 2D-optoelectronics devices.