Tuning Carrier Tunneling in van der Waals Heterostructures for Ultrahigh Detectivity

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• 作者：Quoc An Vu ; Jin Hee LeeVan Luan Nguyen ; Yong Seon Shin ; Seong Chu Lim ; Kiyoung LeeJinseong Heo ; Seongjun Park ; Kunnyun Kim ; Young Hee Lee ; Woo Jong Yu
• 刊名：Nano Letters
• 出版年：2017
• 出版时间：January 11, 2017
• 年：2017
• 卷：17
• 期：1
• 页码：453-459
• 全文大小：551K
• ISSN：1530-6992

文摘

Semiconducting transition metal dichalcogenides (TMDs) are promising materials for photodetection over a wide range of visible wavelengths. Photodetection is generally realized via a phototransistor, photoconductor, p–n junction photovoltaic device, and thermoelectric device. The photodetectivity, which is a primary parameter in photodetector design, is often limited by either low photoresponsivity or a high dark current in TMDs materials. Here, we demonstrated a highly sensitive photodetector with a MoS₂/h-BN/graphene heterostructure, by inserting a h-BN insulating layer between graphene electrode and MoS₂ photoabsorber, the dark-carriers were highly suppressed by the large electron barrier (2.7 eV) at the graphene/h-BN junction while the photocarriers were effectively tunneled through small hole barrier (1.2 eV) at the MoS₂/h-BN junction. With both high photocurrent/dark current ratio (>10⁵) and high photoresponsivity (180 AW^–1), ultrahigh photodetectivity of 2.6 × 10¹³ Jones was obtained at 7 nm thick h-BN, about 100–1000 times higher than that of previously reported MoS₂-based devices.