Photon-Assisted Electrochemical Deposition of Germanene
Authors: Jung Jin , Ledina Maria , Bui Nhi , Stickney John Lewellen 
Published: February 2020

Germanene, Ge analogue of graphene, is a near-planar 2D Dirac material stable in a low-buckled graphene-like honeycomb geometry and electronic properties.1 Graphene’s interesting features lead to booming interest in graphene, and now we are exploring other elemental group IV 2D materials that have graphene-like geometry and electronic properties such as siliecene2
,3, stanene4
,5, germanane (hydrogenated germanene)6, and germanene.7
,8,9  Theoretical studies of the 2D honeycomb structured germanene (Ge) have been reported earlier10, but experimental evidence of germanene synthesis have been reported only in recent years from various groups utilizing ultra-high vacuum (UHV) system.11 A new photon-assisted electrochemical deposition of germanene has been studied, and evidences for germanene formation are found using in situ scanning tunneling microscope (STM) and in situ Raman spectroelectrochemistry. The STM images show that germanium deposited on a single crystalline gold (111) surface exhibit a honeycomb germanene structure. Using i
n situ surface-enhanced Raman spectroelectrochemistry the germanene peak was reproducibly observed when the germanium deposit was exposed to laser; this peak agrees with the theoretical prediction for the “G-like” mode in germanene and previous experimental result.12
,13

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