Resonant Tunneling and Negative Differential Resistance in Black Phosphorus Vertical Heterostructures
Resonant Tunneling and Negative Differential Resistance in Black Phosphorus Vertical Heterostructures
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DOI：
10.1002/aelm.202000318
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发表时间：
2020-07
影响因子：
6.2
通讯作者：
Kai Xu;Eric Wynne;Wenjuan Zhu
中科院分区：
文献类型：
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作者：
Kai Xu;Eric Wynne;Wenjuan Zhu
具有负差分电阻(NDR)的共振隧穿二极管因其独特的量子共振隧穿现象以及在太赫兹发射/检测和高密度逻辑/存储方面的潜在应用而引起了人们的极大关注。本文探索了共振隧穿器件，其中载流子穿过夹有两个黑磷(BP)层的六方氮化硼(HBN)势垒。当两个黑磷层的能带对齐时，就会发生共振。导电原子力显微镜(CAFM)测量表明，在室温下，NDR峰明显，峰谷比很大。研究发现，负阻峰值的位置对CAFM中使用的电压波形的幅值和形状非常敏感，这可以用电荷陷阱效应来解释。此外，还展示了基于BP/hBN/BP堆栈的共振隧穿晶体管，其中NDR峰的位置可以通过静电选通来调节。与传统的块体材料隧道二极管相比，基于薄氮化硼隧道势垒和高迁移率黑磷的隧道二极管具有超高速的响应能力。这一特性与NDR特性相结合，为太赫兹振荡器和多值逻辑器件提供了潜在的应用。
Resonant tunneling diodes with negative differential resistance (NDR) have attracted significant attention due to their unique quantum resonant tunneling phenomena and potential applications in terahertz emission/detection and high‐density logic/memory. In this paper, resonant tunneling devices, where the carriers tunnel through a hexagonal boron nitride (hBN) barrier sandwiched by two black phosphorus (BP) layers, are explored. The resonance occurs when the energy bands of the two black phosphorus layers are aligned. The conductive atomic force microscopy (CAFM) measurements reveal prominent NDR peaks with large peak‐to‐valley ratios at room temperature. It is found that the positions of the NDR peaks are very sensitive to the amplitude and the shape of the voltage waveform used in CAFM, which can be explained by the charge trapping effect. Furthermore, resonant tunneling transistors are demonstrated based on BP/hBN/BP stacks in which the locations of the NDR peaks are tunable by the electrostatic gating. As compared to the traditional tunneling diodes based on bulk materials, the tunneling devices based on thin boron nitride tunneling barrier and high mobility black phosphorus offer ultra‐high‐speed response. This feature, together with the NDR characteristics, provides the potential for applications in THz oscillators and multi‐value logic devices.