基于WSe2/h-BN/石墨烯异质结的二维可编程光电探测器点击并应用

摘要：基于二维材料的可编程光电光电探测器可以并行调制光信号和电子信号，因此特别适用于光电混合双通道通信。本文，江南大学Haiyan Nan、Shaoqing Xiao等研究人员在《ADVANCED SCIENCE》期刊发表名为“2D Programmable Pho

1成果简介

基于二维材料的可编程光电光电探测器可以并行调制光信号和电子信号，因此特别适用于光电混合双通道通信。本文，江南大学Haiyan Nan、Shaoqing Xiao等研究人员在《ADVANCED SCIENCE》期刊发表名为“2D Programmable Photodetectors Based on WSe2/h-BN/Graphene Heterojunctions”的论文，研究介绍了一种利用二硒化钨（WSe2）、六方氮化硼（h-BN）和石墨烯（Gra）构建的可编程非易失性双极半浮动栅光伏光电探测器（SFG-PD）。通过控制施加到控制栅极的电压脉冲，该器件可产生对立的内置电场结（p-p 和 n-p 结），从而实现正负光响应之间的可逆切换，响应时间最快可达 2.02 µs。此外，还展示了该器件在双通道光电混合通信中的应用，为实现高速、大容量、低损耗和安全的多通道通信提供了实用的解决方案。

2图文导读

图1、Conceptual illustration and characterization of the WSe2/h-BN/Gra heterojunction. a) Schematic diagram of the WSe2/h-BN/Gra semi-floating gate photodetector (WSe2 SFG-PD). b) Flat energy bands of the Au/WSe2/h-BN/graphene heterostructure. c) Optical microscope image of the fabricated WSe2 SFG-PD device. d) Extracted heights of the Gra, h-BN, and WSe2 flakes corresponding to the blue, orange, and green lines of proposed devices (in Figure S2, Supporting Information). e) Raman spectrum of the WSe2/h-BN/Gra heterostructure photodetector.

图2、Implementation of non-volatile p-p/n-p junctions in the WSe+2/h-BN/Gra heterojunction. a) Semi-logarithmic IDS-VDS curves of WSe2 under different gate voltage pulses applied to Si. b) Extraction and fitting of the rectification ratio of WSe2 corresponding to different gate voltage pulses based on the proposed device. c) Operation diagram of the WSe2 SFG-PD device under positive Vcg applied and released to the Si control gate (left), tunneling charges in the SFG layer inducing mirror charge formation in the channel material (middle), and the energy band diagram of the p-p homojunction device (right). d) Operation diagram of the WSe+2 SFG-PD device under negative Vcg applied and released to the Si control gate (left), tunneling charges in the SFG layer inducing mirror charge formation in the channel material (middle), and the energy band diagram of the n-p homojunction device (right). e) Time-dependent semi-logarithmic IDS–VDS curve of WSe2 under a +20 V gate voltage pulse applied on Si. Inset: Fitting curve of IDS as a function of time for WSe2 under a +20 V gate voltage pulse with VDS = +1 V applied to Si.

图3、Reconfigurable photovoltaic characteristics in the WSe2 SFG-PD device. a) Measurement of the switchable electro-optical response of the WSe2 SFG-PD device at different operating wavelengths under varying incident light powers and at 0 V bias. b) Semi-logarithmic output curves under different input optical powers (Pin) with a +20 V voltage pulse applied to Si substrate at 637 nm and 0 V bias. c) Optical response of the WSe2 SFG-PD structure under a ±20 V voltage pulse on Si substrate at 637 nm illumination, 0 V bias, with power switching from 0.038 to 10.23 µW. d,e) Photodetector performance of the device at Vcg-pulse = ±20 V, 0 V bias, and 637 nm, corresponding to responsivity (R) and detectivity (D*). f,g) Photodetector performance of the device at Vcg-pulse = ±20 V, 0 V bias, and 637 nm, corresponding to noise equivalent power (NEP) and external quantum efficiency (EQE). h) Fitting relationship between photocurrent and optical intensity under Vcg-pulse = ±20 and 0 V bias at 637 nm.

图4、Electro-optical response of the WSe2 SFG-PD device under 637 nm illumination, with Vcg-pulse = ±20 and 0 V bias. a) Rise time and fall time of the WSe2 SFG-PD under Vcg-pulse = +20 and 0 V bias. b) Rise time and fall time of the WSe2 SFG-PD under Vcg-pulse = −20 and 0 V bias. Variation of normalized photocurrent in the WSe2 SFG-PD device with laser modulation frequency under c) Vcg-pulse = +20 and 0 V bias. d) Vcg-pulse = −20 and 0 V bias. Normalized optical response characteristics of the WSe2 SFG-PD to different frequency pulse signals under e) Vcg-pulse = +20 and 0 V bias. f) Vcg-pulse = −20 and 0 V bias. g) Comparison of response times of different types of WSe2 heterostructure photodetectors.

图5、Dual-channel optoelectronic hybrid communication. a) Schematic illustration of dual-channel optoelectronic hybrid communication based on the WSe2 SFG-PD device. b) This dual-channel optoelectronic hybrid communication system transmits input and output signals containing information streams “6C5F” and "5357″ and decodes Chinese characters through Unicode encoding.

3小结

利用二维材料的独特性能，我们通过堆叠二维层状结构 WSe2、h-BN 和石墨烯，设计并制造出了 WSe2 SFG-PD 器件。通过操纵背栅极的电压脉冲，电荷载流子可以在石墨烯浮动栅极中存储和擦除。利用这种方法，我们成功实现了一种可编程的非易失性自驱动光电探测器，它具有超快的响应/恢复速度（8.77 微秒/2.02 微秒和 5.92 微秒/7.80 微秒）、高响应率（2.76 A/W 和 1. 63 A/W ）、高比检出率（7.86 × 1011 琼斯和 4.42 × 1011 琼斯）、低噪声等效功率（4.76 × 10-15 W/Hz1/2 和 8.47 × 10-15 W/Hz1/2）、外部量子效率（537% 和 318%）以及出色的保持性能（>2 × 103 秒）。此外，该器件还能产生相对对称、方向相反的内置电场（p-p/n-p 结）。在此基础上，我们通过产生平衡的三元电信号实现了双通道光电混合通信，实现了高速、大容量、低损耗和高安全性。这表明，WSe+2 SFG-PD器件为光电混合通信提供了一种快速、有效、便捷的新选择。

文献：