论文标题
栅极可调Trion开关用于激子设备应用程序
Gate-tunable trion switch for excitonic device applications
论文作者
论文摘要
TRIONS是具有正电荷或负电荷的激子物种，因此，与中性激子不同，TRIONS的流动可以产生可检测的电荷电流。在有利的掺杂条件下，可以使用谐振激发以连贯的方式创建TRIONS。在这项工作中，我们利用这些属性来证明在几层石墨烯/单层WS2/单层石墨烯垂直异质结中的栅极控制的TRION开关。通过使用WS2夹层层带隙的温度控制变化的高分辨率光谱扫描，我们获得了一个栅极电压依赖于垂直光电流，从而强烈依赖于激发的光谱位置，并且光电流最大化激发能与Trion峰位置恢复时，启动能量最大化。此外，通过不完整的底部单层石墨烯筛选施加的后门电压可以有效地控制这种谐振的光电流，并且光电流与栅极依赖性的trion强度密切相关，而非谐音的光电流仅表现出弱的栅极依赖性依赖性依赖性的光量呈现繁殖的繁殖式呈繁殖式呈繁殖。我们估计设备的100 fs切换时间。这些发现可用于演示分层材料中超快速的激子设备。
Trions are excitonic species with a positive or negative charge, and thus, unlike neutral excitons, the flow of trions can generate a net detectable charge current. Trions under favourable doping conditions can be created in a coherent manner using resonant excitation. In this work, we exploit these properties to demonstrate a gate controlled trion switch in a few-layer graphene/monolayer WS2/monolayer graphene vertical heterojunction. By using a high resolution spectral scan through a temperature controlled variation of the bandgap of the WS2 sandwich layer, we obtain a gate voltage dependent vertical photocurrent strongly relying on the spectral position of the excitation, and the photocurrent maximizes when the excitation energy is resonant with the trion peak position. Further, the resonant photocurrent thus generated can be effectively controlled by a back gate voltage applied through the incomplete screening of the bottom monolayer graphene, and the photocurrent strongly correlates with the gate dependent trion intensity, while the non-resonant photocurrent exhibits only a weak gate dependence -unambiguously proving a trion driven photocurrent generation under resonance. We estimate a sub-100 fs switching time of the device. The findings are useful towards demonstration of ultra-fast excitonic devices in layered materials.
