Kim Donguk, Lee Hyemin, Song Minwoo, Nam Jongwoo, Lee Changjun, Woo Jaeyong, Jang Juntae, Jeong Minsu, Yeo Hyeonwoo, Lee Ryong-Gyu, Park Eunje, Choi Hyeonmin, Kim Yong-Hoon, Kang Keehoon, Lee Takhee
Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
Sci Adv. 2025 Jun 20;11(25):eadt3603. doi: 10.1126/sciadv.adt3603. Epub 2025 Jun 18.
The advancement of molecular junction transistors relies heavily on precise modulation of molecular orbitals, yet this is hindered by a limited transmission window and reduced bias stability, which typically restricts the range of active channel molecules adopted to those with orbital levels near Fermi level of the contacts. In this study, we demonstrate an effective orbital gating of prototypical alkanethiol-based molecules with deeper orbital levels in vertical large-area mixed self-assembled monolayers (SAMs) configuration that offers enhanced electrical bias stability and gating efficiency. By using ion gel gating in Au-molecule-graphene junction, the channel conductance could be modulated notably according to a clear transition from direct tunneling to Fowler-Nordheim tunneling regime. The mixed SAM molecular transistors also showed a superior gating efficiency due to the suppressed field screening effect by the net molecular dipole. This work is expected to contribute toward developing reliable three-terminal molecular device platform extended to molecules with deep orbital levels.
分子结晶体管的发展在很大程度上依赖于分子轨道的精确调制，然而这受到有限的传输窗口和降低的偏置稳定性的阻碍，这通常将所采用的有源沟道分子的范围限制为轨道能级接近接触电极费米能级的那些分子。在本研究中，我们展示了在垂直大面积混合自组装单分子层（SAMs）配置中对具有更深轨道能级的典型烷硫醇基分子进行有效的轨道门控，该配置提供了增强的电偏置稳定性和门控效率。通过在金-分子-石墨烯结中使用离子凝胶门控，通道电导可以根据从直接隧穿到福勒-诺德海姆隧穿机制的明显转变而显著调制。由于净分子偶极子抑制了场屏蔽效应，混合SAM分子晶体管还表现出优异的门控效率。这项工作有望为开发可靠的三端分子器件平台做出贡献，该平台可扩展到具有深轨道能级的分子。
