UV illumination enhanced desorption of oxygen molecules from monolayer MoS2 surface

Wang, Yuhang; He, Zhiquan; Zhang, Jinbing; Líu, Hao; Lai, Xubo; Liu, Boyang; Chen, Yibao; Wang, Fengping; Zhang, Liuwan

doi:10.1007/s12274-020-2614-2

Cited by 27 publications

(22 citation statements)

References 37 publications

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“…These holes are responsible for the p-type conductivity and the higher carrier density measured at atmospheric pressure. When the material is exposed to light, oxygen is easily removed from the surface [46] and the free electrons can recombine with the holes in the material (Figure 3d). A similar behavior has been already reported for MoS 2 phototransistors.…”

Section: Resultsmentioning

confidence: 99%

Coexistence of Negative and Positive Photoconductivity in Few‐Layer PtSe₂ Field‐Effect Transistors

Grillo

Faella

Pelella

et al. 2021

Adv Funct Materials

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Platinum diselenide (PtSe 2 ) field-effect transistors with ultrathin channel regions exhibit p-type electrical conductivity that is sensitive to temperature and environmental pressure. Exposure to a supercontinuum white light source reveals that positive and negative photoconductivity coexists in the same device. The dominance of one type of photoconductivity over the other is controlled by environmental pressure. Indeed, positive photoconductivity observed in high vacuum converts to negative photoconductivity when the pressure is raised. Density functional theory calculations confirm that physisorbed oxygen molecules on the PtSe 2 surface act as acceptors. The desorption of oxygen molecules from the surface, caused by light irradiation, leads to decreased carrier concentration in the channel conductivity. The understanding of the charge transfer occurring between the physisorbed oxygen molecules and the PtSe 2 film provides an effective route for modulating the density of carriers and the optical properties of the material.

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Section: Resultsmentioning

confidence: 99%

Coexistence of Negative and Positive Photoconductivity in Few‐Layer PtSe₂ Field‐Effect Transistors

Grillo

Faella

Pelella

et al. 2021

Adv Funct Materials

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“…The device exhibits reproducible characteristics under multiple light on‐off switching cycles with the response and recovery times (defined as the time between 10% and 90% of the maximum photocurrent and vice versa) being ≈2.1 and 3.6 s, respectively (Figure S3b, Supporting Information). The values of responsivity and detectivity with moderate response time of this Mo 0.5 W 0.5 S 2 alloy UV detector are superior to the previously reported devices [ 46,47 ] The fabricated photodetector ( x = 0.5) exhibits an excellent stability, with the photocurrent under UV (365 nm, 27.55 µW cm −2 ) illumination remaining almost unchanged even after six months of its fabrication (Figure S3c, Supporting Information).…”

Section: Resultsmentioning

confidence: 68%

Two‐Dimensional Mo_xW_1−xS₂ Alloys for Nanogenerators Producing Record Piezo‐Output and Coupled Photodetectors for Self‐Powered UV Sensor

Bhattacharya

Mukherjee

Pal

et al. 2022

Advanced Optical Materials

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light-sensing devices, photodetectors have wide range of applications in the field of security, ultraviolet (UV) radiation detection, infrared thermal imaging, remote sensing, communication system etc. Various traditional semiconductors (Si, Ge, ZnO, GaN, TiO 2 , etc.) and recently two-dimensional materials, specially transition metal dichalcogenides (TMDCs) are attractive in photodetection applications due to their fascinating optoelectronic properties. The wide application of

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“…To investigate the change in the current I under illumination, we choose three different wavelengths: A wavelength of λ exc = 442 nm excites the heterostructure at its point of maximum extinction, while a wavelength of λ exc = 632 nm leads to absorption slightly above the A exciton resonance energy in MoS 2 . Additionally, we used UV excitation at λ exc = 325 nm, which is known to facilitate the removal of surface adsorbates in 2D materials like MoS 2 . Ambient (10 3 hPa) as well as vacuum conditions (10 –6 hPa) are used for the experiments to investigate the impact of environmental conditions on the photocurrent.…”

Section: Resultsmentioning

confidence: 99%

Role of Surface Adsorbates on the Photoresponse of (MO)CVD-Grown Graphene–MoS₂ Heterostructure Photodetectors

Beckmann

Grundmann

Daniel

et al. 2022

ACS Appl. Mater. Interfaces

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A promising strategy toward ultrathin, sensitive photodetectors is the combination of a photoactive semiconducting transition-metal dichalcogenide (TMDC) monolayer like MoS2 with highly conductive graphene. Such devices often exhibit a complex and contradictory photoresponse as incident light can trigger both photoconductivity and photoinduced desorption of molecules from the surface. Here, we use metal–organic chemical vapor deposition (MOCVD) to directly grow MoS2 on top of graphene that is deposited on a sapphire wafer via chemical vapor deposition (CVD) for realizing graphene–MoS2 photodetectors. Two-color optical pump–electrical probe experiments allow for separation of light-induced carrier transfer across the graphene–MoS2 heterointerface from adsorbate-induced effects. We demonstrate that adsorbates strongly modify both magnitude and sign of the photoconductivity. This is attributed to a change of the graphene doping from p- to n-type in case adsorbates are being desorbed, while in either case, photogenerated electrons are transferred from MoS2 to graphene. This nondestructive probing method sheds light on the charge carrier transfer mechanisms and the role of adsorbates in two-dimensional (2D) heterostructure photodetectors.

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UV illumination enhanced desorption of oxygen molecules from monolayer MoS2 surface

Cited by 27 publications

References 37 publications

Coexistence of Negative and Positive Photoconductivity in Few‐Layer PtSe₂ Field‐Effect Transistors

Coexistence of Negative and Positive Photoconductivity in Few‐Layer PtSe₂ Field‐Effect Transistors

Two‐Dimensional Mo_xW_1−xS₂ Alloys for Nanogenerators Producing Record Piezo‐Output and Coupled Photodetectors for Self‐Powered UV Sensor

Role of Surface Adsorbates on the Photoresponse of (MO)CVD-Grown Graphene–MoS₂ Heterostructure Photodetectors

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UV illumination enhanced desorption of oxygen molecules from monolayer MoS2 surface

Cited by 27 publications

References 37 publications

Coexistence of Negative and Positive Photoconductivity in Few‐Layer PtSe2 Field‐Effect Transistors

Coexistence of Negative and Positive Photoconductivity in Few‐Layer PtSe2 Field‐Effect Transistors

Two‐Dimensional MoxW1−xS2 Alloys for Nanogenerators Producing Record Piezo‐Output and Coupled Photodetectors for Self‐Powered UV Sensor

Role of Surface Adsorbates on the Photoresponse of (MO)CVD-Grown Graphene–MoS2 Heterostructure Photodetectors

Contact Info

Product

Resources

About

Coexistence of Negative and Positive Photoconductivity in Few‐Layer PtSe₂ Field‐Effect Transistors

Coexistence of Negative and Positive Photoconductivity in Few‐Layer PtSe₂ Field‐Effect Transistors

Two‐Dimensional Mo_xW_1−xS₂ Alloys for Nanogenerators Producing Record Piezo‐Output and Coupled Photodetectors for Self‐Powered UV Sensor

Role of Surface Adsorbates on the Photoresponse of (MO)CVD-Grown Graphene–MoS₂ Heterostructure Photodetectors