Direct Growth of Germanene at Interfaces between Van der Waals Materials and Ag(111). (12th November 2020)

• Record Type: Journal Article
• Authors: Suzuki, Seiya; Iwasaki, Takuya; De Silva, K. Kanishka H.; Suehara, Shigeru; Watanabe, Kenji; Taniguchi, Takashi; Moriyama, Satoshi; Yoshimura, Masamichi; Aizawa, Takashi; Nakayama, Tomonobu
• Is Part Of: Advanced functional materials. Volume 31:Number 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-12
• Subjects: density functional theory -- germanene -- graphene -- hexagonal boron nitride -- Raman spectroscopy -- van der Waals materials; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202007038
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Germanene, a 2D honeycomb germanium crystal, is grown at graphene/Ag(111) and hexagonal boron nitride (h‐BN)/Ag(111) interfaces by segregating germanium atoms. A simple annealing process in N2 or H2 /Ar at ambient pressure leads to the formation of germanene, indicating that an ultrahigh‐vacuum condition is not necessary. The grown germanene is stable in air and uniform over the entire area covered with a van der Waals (vdW) material. As an important finding, it is necessary to use a vdW material as a cap layer for the present germanene growth method since the use of an Al2 O3 cap layer results in no germanene formation. The present study also proves that Raman spectroscopy in air is a powerful tool for characterizing germanene at the interfaces, which is concluded by multiple analyses including first‐principles density functional theory calculations. The direct growth of h‐BN‐capped germanene on Ag(111), which is demonstrated in the present study, is considered to be a promising technique for the fabrication of future germanene‐based electronic devices. Abstract : Direct growth method of germanene at interfaces between van der Waals (vdW) materials and Ag(111) is proposed and developed. The grown germanene is stable in air, which enables its handling in air. A vdW interface provides a nanoscale platform for growing germanene similarly to that in vacuum, which cannot be achieved with a typical oxide interface such as Al2 O3 .