Redox-governed charge doping dictated by interfacial diffusion in two-dimensional materials

Park, Kwanghee; Kang, Hyun Joon; Koo, Seonghyun; Lee, DaeEung; Ryu, Sunmin

doi:10.1038/s41467-019-12819-w

Cited by 31 publications

(88 citation statements)

References 33 publications

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“…We suspect the opposite gate-dependent PL emissions result from p-doping and n-doping of WSe 2 on Au and SiO 2 , which is caused by charge-transfer effect [21][22][23][24] and chemical-doping effect, [25][26][27] respectively. The work function of Au is about −5.4 eV, [28] which is lower than the conduction band (CB) minimum of WSe 2 (about −3.2 eV).…”

Section: Mechanism Of the Opposite Behavior Of Excitonic Emissions Upon Gate Voltagementioning

confidence: 90%

Room‐Temperature Exciton‐Based Optoelectronic Switch

Zhou

Liu

et al. 2021

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Excitons, bound pairs of electrons and holes, could act as an intermediary between electronic signal processing and optical transmission, thus speeding up the interconnection of photoelectric communication. However, up to date, exciton‐based logic devices such as switches that work at room temperature are still lacking. This work presents a prototype of a room‐temperature optoelectronic switch based on excitons in WSe2 monolayer. The emission intensity of WSe2 stacked on Au and SiO2 substrates exhibits completely opposite behaviors upon applying gate voltages. Such observation can be ascribed to different doping behaviors of WSe2 caused by charge‐transfer and chemical‐doping effect at WSe2/Au and WSe2/SiO2 interfaces, respectively, together with the charge‐drift effect. These interesting features can be utilized for optoelectronic switching, confirmed by the cyclic PL switching test for a long time exceeding 4000 s. This study offers a universal and reliable approach for the fabrication of exciton‐based optoelectronic switches, which would be essential in integrated nanophotonics.

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Section: Mechanism Of the Opposite Behavior Of Excitonic Emissions Upon Gate Voltagementioning

confidence: 90%

Room‐Temperature Exciton‐Based Optoelectronic Switch

Zhou

Liu

et al. 2021

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“…In the air, the main ambient components such as H2O and O2 would adsorb on TMDCs and influence their conduction types. In the characterization of doping result, photoluminescence (PL) spectrum is an effective method because PL peak intensities and positions would be regulated by the carrier distribution [42]. With H2O and O2 adsorbates, the PL spectra demonstrated a significant intensity enhancement for MoS2 and an opposite change for WSe2 (Figs.…”

Section: Surface Adsorptionmentioning

confidence: 99%

“…With H2O and O2 adsorbates, the PL spectra demonstrated a significant intensity enhancement for MoS2 and an opposite change for WSe2 (Figs. 5(a) and 5(b)) that could be specifically explained through the carrier recombination theory [41,42]. The carrier recombinations consist of nonradiative recombination and radiative recombination (PL spectrum) which is further divided into exciton recombination (X 0 ) and trion recombination (X +/-).…”

Section: Surface Adsorptionmentioning

confidence: 99%

“…However, the p-/n-type modulation of TMDCs is quite different from that of bulk materials. Their unique characteristic of ultrahigh specific surface area makes them extremely sensitive to crystal defects [37][38][39], impurities [40][41][42][43], contacts [15,[44][45][46][47][48][49], and interfaces [43,[50][51][52], which would largely interfere with the real p/n-type levels and bring a huge challenge to the applications of TMDC-based devices. Nevertheless, their atomically thin thickness also presents some new possible approaches in modulating their p-/n-type levels by controlling the sensitive factors aforementioned [53][54][55][56].…”

Section: Introductionmentioning

confidence: 99%

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p-/n-Type modulation of 2D transition metal dichalcogenides for electronic and optoelectronic devices

Ouedraogo

et al. 2021

Nano Res.

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Two-dimensional layered transition metal dichalcogenides (TMDCs) have demonstrated a huge potential in the broad fields of optoelectronic devices, logic electronics, electronic integration, as well as neural networks. To take full advantage of TMDC characteristics and efficiently design the device structures, one of the most key processes is to control their p-/n-type modulation. In this review, we summarize the p-/n-type modulation of TMDCs based on diverse strategies consisting of intrinsic defect tailoring, substitutional doping, surface charge transfer, chemical intercalation, electrostatic modulation, and dielectric interface engineering. The modulation mechanisms and comparisons of these strategies are analyzed together with a discussion of their corresponding device applications in electronics and optoelectronics. Finally, challenges and outlooks for p-/n-type modulation of TMDCs are presented to provide references for future studies.

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“…Electrical hysteresis has been observed in devices based on two-dimensional materials, such as graphene and TMDs based fieldeffect transistors 29,30 . Generally, electrical hysteresis is attributed to the chemical-doping effect by doping species (O2 and H2O) that are bound at the device/substrate interface, and/or on the surface of the device [31][32][33] . In our case, we propose that the excitonic hysteresis mentioned above is originated from the same scenario.…”

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confidence: 99%

Interlayer-Exciton Based Nonvolatile Valleytronic Memory

Ye¹,

Shen²,

Ren³

et al. 2020

Preprint

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Analogous to conventional charge-based electronics, valleytronics aims at encoding data via valley degree of freedom, enabling new routes for information processing. Long-lived interlayer excitons (IXs) in van der Waals heterostructures (HSs) stacked by transition metal dichalcogenides (TMDs) carry valley-polarized information and thus would find promising applications in valleytronic devices. Although great progress of IX based valleytronic devices has been achieved, nonvolatile valleytronic memories are still challenging. Here, we demonstrate IX based nonvolatile valleytronic memory in a WS2/WSe2 HS. The emission characteristics of IX exhibit a large excitonic/valleytronic hysteresis upon cyclic-voltage sweeping. Importantly, IX emission can be electrically switched between a bright state and a dark state with large light-intensity and helicity contrast of about 1.7 and 1.8, respectively, which can be ascribed to the chemical-doping of O2/H2O redox couple between TMDs and substrate. Taking advantage of the large hysteresis, IX can be utilized for manipulating and nonvolatile storing valley information and IX based nonvolatile valleytronic memory has been successfully demonstrated. These findings open up an avenue for nonvolatile valleytronic memory and would motivate more investigations on valleytronic devices.

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Redox-governed charge doping dictated by interfacial diffusion in two-dimensional materials

Cited by 31 publications

References 33 publications

Room‐Temperature Exciton‐Based Optoelectronic Switch

Room‐Temperature Exciton‐Based Optoelectronic Switch

p-/n-Type modulation of 2D transition metal dichalcogenides for electronic and optoelectronic devices

Interlayer-Exciton Based Nonvolatile Valleytronic Memory

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