Tip-Mediated Bandgap Tuning for Monolayer Transition Metal Dichalcogenides
ACS Nano
Meng-Kai Lin, Guan-Hao Chen, Ciao-Lin Ho, Wei-Chen Chueh, Joseph Andrew Hlevyack, Chia-Nung Kuo, Tsu-Yi Fu, Juhn-Jong Lin, Chin Shan Lue, Wen-Hao Chang, Noriaki Takagi, Ryuichi Arafune, Tai-Chang Chiang, and Chun-Liang Lin
Tip-Mediated Bandgap Tuning for Monolayer Transition Metal Dichalcogenides
單層材料的物理特性與調控機制解明是做為新穎電子元件設計的基石，本研究由中央大學物理系林孟凱教授、陽明交通大學林俊良教授與美國伊利諾大學江台章院士主導。我們透過掃描穿遂顯微術/電子譜比較單層的MoS2和PtTe2材料電子結構隨穿遂電流的響應，發現單層MoS2的能隙隨著穿遂電流增加呈現指數遞減；反之PtTe2單層則隨著穿遂電流增加，展現出半導體-金屬電性轉變行為，且是一個可逆過程。藉由理論輔助，我們提出單層過渡金屬硫化物電性調控的兩個機制，分別為電場驅動響應(MoS2)以及電子態混成(PtTe2)的作用。此研究將在電子元件的電性調控上有著重要意義。
Physical properties of monolayer materials are keys of developing novel electronic devices. The research project leading by Prof. Meng-Kai Lin (NCU), Prof. Chun-Liang Lin (NYCU), and Prof. Tai-Chang Chiang (UIUC) discovers two mechanisms of fulfilling bandgap engineering in transition metal dichalcogenides down to monolayers by scanning tunneling microscopy/spectroscopy. Bandgap reduction with increasing tunneling current in the tip-MoS2 system suggests an electric-field-induced gap renormalization effect. By contrast, a reversible semiconductor-to-metal transition occurs at a moderate tunneling current in the tip-PtTe2 system suggests an electronic coupling in between the electronic states of tip and PtTe2 film. The finding is of significant implications regarding methods and the principles for bandgap engineering of monolayer transition metal dichalcogenides.