Hybrid graphene-quantum dot phototransistors with ultrahigh gain
Hybrid graphene-quantum dot phototransistors with ultrahigh gain
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DOI：
10.1038/nnano.2012.60
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发表时间：
2012-06-01
影响因子：
38.3
通讯作者：
Koppens, Frank H. L.
中科院分区：
文献类型：
--
作者：
Konstantatos, Gerasimos;Badioli, Michela;Koppens, Frank H. L.
石墨烯是光电子学（1）和光电探测应用（2-6）的有吸引力的材料，因为它提供了宽的光谱带宽和快速的响应时间。然而，弱的光吸收和可以从一个入射光子产生多个电荷载流子的增益机制的缺乏已经将基于石墨烯的光电探测器的响应度限制为类似于10（-2）AW（-1）。在这里，我们证明了在由单层或双层石墨烯覆盖的胶体量子点薄膜组成的混合光电探测器中，每个光子的增益类似于10（8）电子，响应度类似于10（7）AW（-1）。量子点层中强且可调的光吸收产生转移到石墨烯的电荷，由于石墨烯的高电荷迁移率和量子点层中的长捕获电荷寿命，它们在石墨烯中多次再循环。该器件的比探测率为7 x10（13）琼斯，受益于门可调灵敏度和速度，从短波红外到可见光的光谱选择性，以及与当前电路技术的兼容性。
Graphene is an attractive material for optoelectronics(1) and photodetection applications(2-6) because it offers a broad spectral bandwidth and fast response times. However, weak light absorption and the absence of a gain mechanism that can generate multiple charge carriers from one incident photon have limited the responsivity of graphene-based photodetectors to similar to 10(-2) AW(-1). Here, we demonstrate a gain of similar to 10(8) electrons per photon and a responsivity of similar to 10(7) AW(-1) in a hybrid photodetector that consists of monolayer or bilayer graphene covered with a thin film of colloidal quantum dots. Strong and tunable light absorption in the quantum-dot layer creates electric charges that are transferred to the graphene, where they recirculate many times due to the high charge mobility of graphene and long trapped-charge lifetimes in the quantum-dot layer. The device, with a specific detectivity of 7x10(13) Jones, benefits from gate-tunable sensitivity and speed, spectral selectivity from the short-wavelength infrared to the visible, and compatibility with current circuit technologies.