Theoretical Insight into Quantum Transport Via Molecular Dots in a Vertical Tunnel Transistor
Theoretical Insight into Quantum Transport Via Molecular Dots in a Vertical Tunnel Transistor
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DOI：
10.1021/acsaelm.0c01056
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发表时间：
2021-02-12
影响因子：
4.7
通讯作者：
Hayakawa, Ryoma
中科院分区：
文献类型：
--
作者：
Basu, Tuhin Shuvra;Wakayama, Yutaka;Hayakawa, Ryoma
我们为C-60分子在垂直晶体管中的量子输运提供了理论上的见解。该器件的一个特点是，晶体管沟道由基于金属-氧化物-半导体(MOS)结构的双隧道结组成，其中分子彼此隔离，然后作为量子点嵌入MOS结构的绝缘层中。因此，即使在宏观设备中，晶体管也允许我们检查单个分子诱导的量子传输。这项研究的一个重要发现是，隧道运输遵循被广泛用于单载波运输的正统理论。模拟的漏极电流-漏极电压曲线和微分电导(Di(D)/dV(D))曲线较好地再现了实验结果。值得注意的是，从简并分子轨道得到的Di(D)/dv(D)峰的间隔与单个或少数C-60分子的荷电能相吻合。这些结果证实了输运可以解释为库仑阻塞和离散分子轨道之间相互作用的单载流子隧穿。此外，理论工作还揭示了输运的温度依赖性是由分子中的量子限制效应引起的本征行为。因此，我们的发现为实现具有吸引人的分子功能的大规模集成单载流子晶体管铺平了道路。
We provide a theoretical insight into the quantum transport of C-60 molecules in a vertical transistor. A feature of the device is that the transistor channel is composed of a double tunnel junction based on a metal-oxide-semiconductor (MOS) structure, where the molecules are isolated from each other and are then embedded as quantum dots in the insulating layer of the MOS structure. The transistor thus allows us to examine quantum transport induced by the individual molecules even in a macroscopic device. A significant finding of this study is that the tunnel transport followed an orthodox theory that is widely used for single-carrier transport. The simulated drain current-drain voltage curves and differential conductance (dI(d)/dV(d)) curves well reproduced those obtained experimentally. Notably, the intervals of the dI(d)/dV(d) peaks derived from the degenerate molecular orbitals coincided with the charging energy of single or a few C-60 molecules. These results confirm that the transport can be interpreted as single-carrier tunneling with interplay between a Coulomb blockade and discrete molecular orbitals. Furthermore, the theoretical work revealed that the temperature dependence of the transport was intrinsic behavior caused by the quantum confinement effect in the molecules. Our findings therefore pave the way to achieving a large-scale integrated single-carrier transistor with attractive molecular functions.