Hot Carrier Transfer in graphene/PtSe2 Heterostructure Tuned by Built-in Electric Field

Van der Waals heterojunction involving graphene (Gr) with transition metal dichalcogenides (TMDs) is regard as a promising structure for their outstanding performance in optical and optoelectronic response. The electron-hole thermalization has been deemed to be the main reason for the sub-bandgap-excitation charge transfer from Gr to TMDs. However, the role of the intricate interlayer interaction of the Gr and the TMDs still require intensive investigation. Here, we have investigated the photocarrier dynamics in 5-layer PtSe2/Gr heterojunction by using time-resolved optical pump and terahertz probe spectroscopy. Interestingly, after photoexcitation, electron transfer from PtSe2 to Gr in PtSe2/Gr/substrate heterojunction has been demonstrated successfully, by contrast, no observable charge transfer occurs in the Gr/PtSe2/substrate heterostructure. The prominent difference for the different stacking sequence between Gr and PtSe2 can be ascribed to the effective built-in field introduced by fused silica substrate. A physical picture accounting for built-in electric field introduced by substrate has been proposed to interpret the charge transfer process in the TMD/Gr heterostructure–the substrate built-in electric field plays a dominated role for controlling the charge transfer pathway in the TMDs/Gr heterojunction. This study not only shed the light to the substrate engineering but also provide a new insight into the dynamic in Gr/TMDs heterojunction, which provides a new method to optimize the performance of photodetection.

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Photoinduced charge transfer from vacuum-deposited molecules to single-layer transition metal dichalcogenides

Japanese Journal of Applied Physics ◽

10.7567/jjap.55.065201 ◽

2016 ◽

Vol 55 (6) ◽

pp. 065201 ◽

Cited By ~ 7

Author(s):

Kazuki Osada ◽

Masatoshi Tanaka ◽

Shinya Ohno ◽

Takanori Suzuki

Keyword(s):

Charge Transfer ◽

Transition Metal ◽

Transition Metal Dichalcogenides ◽

Single Layer ◽

Photoinduced Charge Transfer ◽

Layer Transition ◽

Metal Dichalcogenides ◽

Photoinduced Charge

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Long-lived charge separation following pump-wavelength–dependent ultrafast charge transfer in graphene/WS2 heterostructures

Science Advances ◽

10.1126/sciadv.abd9061 ◽

2021 ◽

Vol 7 (9) ◽

pp. eabd9061

Author(s):

Shuai Fu ◽

Indy du Fossé ◽

Xiaoyu Jia ◽

Jingyin Xu ◽

Xiaoqing Yu ◽

...

Keyword(s):

Charge Transfer ◽

Charge Separation ◽

Transient Absorption ◽

Transition Metal Dichalcogenides ◽

Thermionic Emission ◽

Great Promise ◽

Metal Dichalcogenides ◽

Ultrafast Charge Transfer ◽

Device Operation ◽

Interfacial Charge

Van der Waals heterostructures consisting of graphene and transition metal dichalcogenides have shown great promise for optoelectronic applications. However, an in-depth understanding of the critical processes for device operation, namely, interfacial charge transfer (CT) and recombination, has so far remained elusive. Here, we investigate these processes in graphene-WS2 heterostructures by complementarily probing the ultrafast terahertz photoconductivity in graphene and the transient absorption dynamics in WS2 following photoexcitation. We observe that separated charges in the heterostructure following CT live extremely long: beyond 1 ns, in contrast to ~1 ps charge separation reported in previous studies. This leads to efficient photogating of graphene. Furthermore, for the CT process across graphene-WS2 interfaces, we find that it occurs via photo-thermionic emission for sub-A-exciton excitations and direct hole transfer from WS2 to the valence band of graphene for above-A-exciton excitations. These findings provide insights to further optimize the performance of optoelectronic devices, in particular photodetection.

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Enhanced Raman Scattering of Rhodamine 6G Films on Two-Dimensional Transition Metal Dichalcogenides Correlated to Photoinduced Charge Transfer

Chemistry of Materials ◽

10.1021/acs.chemmater.5b03714 ◽

2015 ◽

Vol 28 (1) ◽

pp. 180-187 ◽

Cited By ~ 61

Author(s):

Youngbin Lee ◽

Hyunmin Kim ◽

Jinhwan Lee ◽

Seong Hun Yu ◽

Euyheon Hwang ◽

...

Keyword(s):

Charge Transfer ◽

Transition Metal ◽

Raman Scattering ◽

Rhodamine 6G ◽

Transition Metal Dichalcogenides ◽

Two Dimensional ◽

Photoinduced Charge Transfer ◽

Metal Dichalcogenides ◽

Enhanced Raman Scattering ◽

Photoinduced Charge

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THE ELECTRONIC STRUCTURE AT ORGANIC–2D MATERIAL HETEROINTERFACES

Surface Review and Letters ◽

10.1142/s0218625x21400035 ◽

2021 ◽

pp. 2140003

Author(s):

YU LI HUANG ◽

ANDREW THYE SHEN WEE

Keyword(s):

Charge Transfer ◽

Electronic Structures ◽

Transition Metal Dichalcogenides ◽

2D Material ◽

Physical Mechanisms ◽

Wide Range ◽

Fundamental Understanding ◽

Potential Applications ◽

Metal Dichalcogenides ◽

Interfacial Charge

Organic–2D material heterostructures have attracted intensive research interest due to their intriguing properties, with a wide range of potential applications in multifunctional flexible electronic and optoelectronic devices. Central to the realization of such devices is a fundamental understanding of the electronic structures at organic–2D material heterointerfaces. The energy level alignment (ELA) at the interface is of paramount importance because it determines the charge transfer barriers between the two materials in contact. In this paper, we discuss the physical mechanisms determining the ELAs, with special attention on interfacial charge transfer at the heterostructures. We review the current understanding of electronic properties at the heterointerfaces formed by the integration of organics with graphene and 2D transition metal dichalcogenides (TMDs), and conclude with a perspective on the future development of organic–2D material heterostructure.

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Exciton manipulation in rippled transition metal dichalcogenides

Nanoscale ◽

10.1039/d0nr05602b ◽

2020 ◽

Vol 12 (41) ◽

pp. 21124-21130

Author(s):

Chen Long ◽

Ying Dai ◽

Jianwei Li ◽

Hao Jin

Keyword(s):

Transition Metal ◽

Electric Field ◽

Transition Metal Dichalcogenides ◽

Spatial Separation ◽

Morphological Control ◽

Metal Dichalcogenides

Due to the introduction of morphological control, the excitons are pushed towards the regions with higher stress. In addition, combined with intrinsic electric field, a spatial separation of photo-excited electrons and holes is achieved.

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Additive manufacturing of patterned 2D semiconductor through recyclable masked growth

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1816197116 ◽

2019 ◽

Vol 116 (9) ◽

pp. 3437-3442 ◽

Cited By ~ 7

Author(s):

Yunfan Guo ◽

Pin-Chun Shen ◽

Cong Su ◽

Ang-Yu Lu ◽

Marek Hempel ◽

...

Keyword(s):

Electronic Materials ◽

Field Effect Transistors ◽

2D Materials ◽

Direct Synthesis ◽

Scale Up ◽

Transition Metal Dichalcogenides ◽

Chemical Vapor ◽

Great Promise ◽

Substrate Engineering ◽

Metal Dichalcogenides

The 2D van der Waals crystals have shown great promise as potential future electronic materials due to their atomically thin and smooth nature, highly tailorable electronic structure, and mass production compatibility through chemical synthesis. Electronic devices, such as field effect transistors (FETs), from these materials require patterning and fabrication into desired structures. Specifically, the scale up and future development of “2D”-based electronics will inevitably require large numbers of fabrication steps in the patterning of 2D semiconductors, such as transition metal dichalcogenides (TMDs). This is currently carried out via multiple steps of lithography, etching, and transfer. As 2D devices become more complex (e.g., numerous 2D materials, more layers, specific shapes, etc.), the patterning steps can become economically costly and time consuming. Here, we developed a method to directly synthesize a 2D semiconductor, monolayer molybdenum disulfide (MoS2), in arbitrary patterns on insulating SiO2/Si via seed-promoted chemical vapor deposition (CVD) and substrate engineering. This method shows the potential of using the prepatterned substrates as a master template for the repeated growth of monolayer MoS2 patterns. Our technique currently produces arbitrary monolayer MoS2 patterns at a spatial resolution of 2 μm with excellent homogeneity and transistor performance (room temperature electron mobility of 30 cm2 V−1 s−1 and on–off current ratio of 107). Extending this patterning method to other 2D materials can provide a facile method for the repeatable direct synthesis of 2D materials for future electronics and optoelectronics.

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