Engineering Electronic Properties of Graphene by Coupling with Si-Rich, Two-Dimensional Islands

详细信息    查看全文

• 作者：Dong Hyun Lee ; Jaeseok Yi ; Jung Min Lee ; Sang Jun Lee ; Yong-Joo Doh ; Hu Young Jeong ; Zonghoon Lee ; Ungyu Paik ; John A. Rogers ; Won Il Park
• 刊名：ACS Nano
• 出版年：2013
• 出版时间：January 22, 2013
• 年：2013
• 卷：7
• 期：1
• 页码：301-307
• 全文大小：500K
• 年卷期：v.7,no.1(January 22, 2013)
• ISSN：1936-086X

文摘

Recent theoretical and experimental studies demonstrated that breaking of the sublattice symmetry in graphene produces an energy gap at the former Dirac point. We describe the synthesis of graphene sheets decorated with ultrathin, Si-rich two-dimensional (2D) islands (i.e., Gr:Si sheets), in which the electronic property of graphene is modulated by coupling with the Si-islands. Analyses based on transmission electron microscopy, atomic force microscopy, and electron and optical spectroscopies confirmed that Si-islands with thicknesses of 2 to 4 nm and a lateral size of several tens of nm were bonded to graphene via van der Waals interactions. Field-effect transistors (FETs) based on Gr:Si sheets exhibited enhanced transconductance and maximum-to-minimum current level compared to bare-graphene FETs, and their magnitudes gradually increased with increasing coverage of Si layers on the graphene. The temperature dependent current鈥搗oltage measurements of the Gr:Si sheet showed approximately a 2-fold increase in the resistance by decreasing the temperature from 250 to 10 K, which confirmed the opening of the substantial bandgap (2.5鈥?.2 meV) in graphene by coupling with Si islands.

Keywords:

graphene; silicon islands; van der Waals growth; bandgap engineering; sublattice asymmetry