点击次数：

论文类型：期刊论文

发表时间：2016-09-29

发表刊物：JOURNAL OF PHYSICAL CHEMISTRY C

收录刊物：SCIE、EI、Scopus

卷号：120

期号：38

页面范围：21691-21698

ISSN号：1932-7447

摘要：Germanene, a two-dimensional (2D) Dirac semi metal beyond graphene, has been recently synthesized on a nonmetallic substrate, which offers great opportunities for realization of germanene-based electronic devices. Understanding the effects of substrate and chemical modification on the electronic properties of germanene is thus crucial for tailoring this novel 2D material for future applications. Herein we investigate the structure, interlayer interaction, and electronic band structure of monolayer germanene supported on various transition metal dichalcogenide (TMD) substrates. A band gap of 38-57 meV can be opened by the TMD substrates due to breaking of lattice symmetry of the germanene sheet: An electron donor molecule, tetrathiafulvalene (TTF), is exploited to noncovalently functionalize the germanene on MoS2 substrate. The electron transfer from TTF to germanene disturbs the Dirac cone of germanene and leads to an augment of the band gap up to 180 meV. Meanwhile, the charge carriers of the hybrid system are still mobile possessing small effective masses (<= 0.16m(0)). Applying a vertical electric field can increase the interface dipole of the hybrid system and further enhance the band gap up to 214 meV. These theoretical results provide an effective and reversible route for engineering the band gap and work function of germanene without severely affecting the transport properties of this material.