Negative photoconductivity of WS2 nanosheets decorated with Au nanoparticles via electron-beam irradiation

Kim, Bong Ho; Kwon, Soon-Hong; Gu, Hyun Ho; Yoon, Young Joon

doi:10.1016/j.physe.2018.10.008

Cited by 27 publications

(10 citation statements)

References 43 publications

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“…However, the ability to switch reversibly and controllably between NPC and PPC is a critical and unexplored requirement for the realization of logic, memory and optical communication technologies. [ 18 ] In addition, NPC, as observed in 2D materials‐based devices, [ 25,26 ] could be related to trap centers, [ 27 ] interaction with adsorbates, [ 28 ] the bolometric effect, [ 29 ] or dependent on gate bias. [ 20 ] The first three mechanisms increase carrier scattering in the device resulting in mobility degradation and negative photocurrent.…”

Section: Introductionmentioning

confidence: 99%

Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS₂ Heterostructure

Jawa

Varghese

Ghosh

et al. 2022

Adv Funct Materials

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Layered 2D van der Waals semiconductors and their heterostructures have been shown to exhibit positive photoconductance (PPC) in many studies. A few recent reports have demonstrated negative photoconductance (NPC) as well that can enable broadband photodetection besides multi‐level optoelectronic logic and memory. Controllable and reversible switching between PPC and NPC is a key requirement for these applications. This report demonstrates visible‐to‐near infrared wavelength‐driven NPC and PPC, along with reversible switching between the two, in an air stable, high mobility, broadband black phosphorus field effect transistor covered with a few layer MoS2 flake. The crossover switching wavelength can be tuned by varying the MoS2 bandgap through its flake thickness and the NPC and PPC photoresponsivities can be modulated using electrostatic gating as well as laser power. Recombination‐driven NPC and PPC, as supported by density functional theory calculations, allows for reversible switching. Further, gate voltage‐dependent negative persistent photoconductance is well‐suited for optosynaptic applications.

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Section: Introductionmentioning

confidence: 99%

Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS₂ Heterostructure

Jawa

Varghese

Ghosh

et al. 2022

Adv Funct Materials

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“…Recent works reveal that the onset of the negative photoconductance in the photodetectors fabricated with the low dimensional materials, such like nanoparticles (Au), nanowires (AlN, ZnO, InAs, and ZnSe) and 2D layers (WS 2 , InN), which is mainly attributed to the oxygen adsorption and photodesorption caused by the surface effects originating from the high surface-to-volume ratio. In order to evaluate the role of oxygen adsorption and photodesorption on the anomalous photoresponse, the device responses, from air to vacuum, have been systematically investigated, as shown in Figures and S7.…”

Section: Results and Discussionmentioning

confidence: 99%

Photoluminescence and Photodetecting Properties of the Hydrothermally Synthesized Nitrogen-Doped Carbon Quantum Dots

Zhao

Zhang

et al. 2019

J. Phys. Chem. C

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Carbon quantum dots (CQDs) have attracted more and more attention as the representative of a new generation of photoluminescence (PL) and photodetecting materials due to their unique optoelectrical properties. However, the formation mechanism of the CQDs as well as the origin of the PL from the CQDs are still open questions to be issued. Here, we report our recent progress on the synthesis of the nitrogen-doped carbon quantum dots (N-CQDs) with a high photoluminescence quantum yield (PLQY) of 97.4% by adjusting the hydrothermal synthesis parameters with citric acid (CA) and ethylenediamine (EDA) as the precursors. The detailed structure and properties indicate that N-CQDs are synthesized by dehydration, condensation, and carbonization, and the PL is attributed to the synergistic effect of the carbogenic core and the surface/molecule state. With the above progress, an all-carbon-based ultraviolet (UV) photodetector is fabricated based on the N-CQDs/graphene hybrid composites, which exhibits a significant negative photoconductivity phenomenon. A maximal negative responsivity up to 2.5 × 104 AW–1 in the UV region has been observed, which was attributed to the two competing mechanisms. One is the oxygen adsorption and photodesorption induced negative photoresponse, while the other is the surface defects in N-CQDs related positive photoconducting. Our work reveals the mechanisms driving force behind the positive and the negative photoconductance phenomenon of photodetectors based on CQDs, which not only contributes to further understanding of the fluorescent and photoresponse mechanisms of CQDs, but also promotes the application potential of CQDs in the field of photodetection and nano-optoelectronic sensors.

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“…In order to eliminate these defects, the photoelectrochemical performance of WS 2 NSs is often improved by doping [23], loading [24] or by compounding with other materials [25]. Hofmann et al chose WS 2 as a platform to expose more active sites through the vertical arrangement.…”

Section: Introductionmentioning

confidence: 99%

A photoelectrochemical sensor based on β‐cyclodextrin‐modified MoS ₂ quantum dots‐WS ₂ nanosheet composites for the detection of benzo [a]pyrene

Shi

Wang

et al. 2022

Micro & Nano Letters

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A photoelectrochemical sensor has been developed for the detection of the polycyclic aromatic hydrocarbon pollutant benzo [a]pyrene (BaP). An n‐butyl lithium intercalation stripping method is applied to prepare tungsten disulphide nanosheets (WS2 NSs). WS2 NSs and β‐cyclodextrin (β‐CD)‐modified MoS2 quantum dots (QDs) are then compounded by hydrogen bonding between the amino and hydroxyl groups. After assembly on an indium tin oxide electrode, the energy level matching and synergistic photoelectric effect between β‐CD‐MoS2 QDs and WS2 NSs reduced the combination of photogenerated electrons and holes and an enhanced photocurrent signal is observed. As a result of the host–guest interaction between β‐CD and BaP, BaP could bind to the β‐CD‐MoS2 QDs in the nanocomposites, which hinders the electron migration to the electrode and weakened the photocurrent signal. Thus, the trace detection of BaP is realized. The rate of photocurrent change is also related to the BaP concentration from 1 to 20 nmol/L with a detection limit of 0.33 nmol/L. In summary, a highly sensitive and selective photoelectrochemical sensor for the detection of BaP is successfully constructed.

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Negative photoconductivity of WS2 nanosheets decorated with Au nanoparticles via electron-beam irradiation

Cited by 27 publications

References 43 publications

Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS₂ Heterostructure

Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS₂ Heterostructure

Photoluminescence and Photodetecting Properties of the Hydrothermally Synthesized Nitrogen-Doped Carbon Quantum Dots

A photoelectrochemical sensor based on β‐cyclodextrin‐modified MoS ₂ quantum dots‐WS ₂ nanosheet composites for the detection of benzo [a]pyrene

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Negative photoconductivity of WS2 nanosheets decorated with Au nanoparticles via electron-beam irradiation

Cited by 27 publications

References 43 publications

Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS2 Heterostructure

Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS2 Heterostructure

Photoluminescence and Photodetecting Properties of the Hydrothermally Synthesized Nitrogen-Doped Carbon Quantum Dots

A photoelectrochemical sensor based on β‐cyclodextrin‐modified MoS 2 quantum dots‐WS 2 nanosheet composites for the detection of benzo [a]pyrene

Contact Info

Product

Resources

About

Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS₂ Heterostructure

Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS₂ Heterostructure

A photoelectrochemical sensor based on β‐cyclodextrin‐modified MoS ₂ quantum dots‐WS ₂ nanosheet composites for the detection of benzo [a]pyrene