Electrical transport and persistent photoconductivity in monolayer MoS<sub>2</sub>phototransistors

Bartolomeo, Antonio Di; Genovese, Luca; Foller, Tobias; Giubileo, Filippo; Luongo, Giuseppe; Croin, Luca; Liang, Shi‐Jun; Ang, L. K.; Schleberger, Marika

doi:10.1088/1361-6528/aa6d98

Cited by 201 publications

(244 citation statements)

References 55 publications

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“…The fast response of the current (stage 2) is attributed to the band‐to‐band transition that creates photoexcitation electrons and holes. After the initial upsurge from the dark current level, the current gradually increases (stage 3) to over one order of magnitude above the dark level, because some photogenerated holes get trapped and attract electrons . When the light is turned off, the current exhibits a rapid drop (stage 4) due to the band‐to‐band transition, and a noticeable PPC follows (stage 5), which is essential for the emulation of the synaptic plasticity in the followings.…”

Section: Resultsmentioning

confidence: 99%

Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS₂

Yang

Zhou

et al. 2018

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Monolayer of 2D transition metal dichalcogenides, with a thickness of less than 1 nm, paves a feasible path to the development of ultrathin memristive synapses, to fulfill the requirements for constructing large-scale high density 3D stacking neuromorphic chips. Herein, memristive devices based on monolayer n-MoS on p-Si substrate with a large self-rectification ratio, exhibiting photonic potentiation and electric habituation, are successfully fabricated. Versatile synaptic neuromorphic functions, such as potentiation/habituation, short-term/long-term plasticity, and paired-pulse facilitation, are successfully mimicked based on the inherent persistent photoconductivity performance and the volatile resistive switching behavior. These findings demonstrate the potential applications of ultrathin transition metal dichalcogenides for memristive synapses. These memristive synapses with the combination of photonic and electric neuromorphic functions have prospective in the applications of synthetic retinas and optoelectronic interfaces for integrated photonic circuits based on mixed-mode electro-optical operation.

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Section: Resultsmentioning

confidence: 99%

Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS₂

Yang

Zhou

et al. 2018

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“…Particularly, Gao et al [19] designed and fabricated a photoelectric memristor based on an In 2 O 3 -SnO 2 /Nb:SrTiO 3 (ITO/Nb:STO) Schottky junction, which exhibited photoresponses over the entire visible spectrum with neuromorphic characteristics, including paired-pulse facilitation (PPF), short-/long-term memory (STM/ LTM), "learning-experience" behavior, and voltage-modulated photoplasticity. First, the photoelectric memristors rely on the persistent photoconductivity effect, [20][21][22][23][24][25] so the DC currents always exist during the device operation. First, the photoelectric memristors rely on the persistent photoconductivity effect, [20][21][22][23][24][25] so the DC currents always exist during the device operation.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

An Artificial Optoelectronic Synapse Based on a Photoelectric Memcapacitor

Zhao

Fan

Cheng

et al. 2019

Adv Elect Materials

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away quickly when the light stimuli are removed. [3][4][5] In other words, traditional photodetectors can detect the images like a retina, but they lack the memory function owned by the visual cortex (see schematic illustration of human visual system in Figure 1a). To realize both detection and memory functions so as to better imitate the human visual system, researchers have attempted to integrate the photodetectors with the nonvolatile memory devices. [6][7][8][9] For example, a bioinspired visual system comprising an In 2 O 3 nanowire photodetector connected in series with an Al 2 O 3 memristor was fabricated recently, which could capture a butterflyshaped image and store it for more than 1 week. [9] In such integrated devices, however, the units responsible for detection, processing, and storage of optical information are physically separated, resulting in high power consumption for data transfer between different units (just as the Von Neumann bottleneck [10,11] ).A simple yet effective humanoid optoelectronic device emerging recently is the artificial optoelectronic synapse based on the photoelectric memristor, which can co-locate the detection and memory functions in a single unit. As the name suggests, a photoelectric memristor can continuously change its resistance upon light stimuli, resembling the physiological The rapid development of artificial intelligence technology has led to the urge for artificial optoelectronic synapses with visual perception and memory capabilities. A new type of artificial optoelectronic synapse, namely a photo electric memcapacitor, is proposed and demonstrated. This photoelectric memcapacitor, with a planar Au/La 1.875 Sr 0.125 NiO 4 /Au metal-semiconductormetal structure, displays a complementary optical and electrical modulation of capacitance, which can be attributed to the charge trapping/detrapping induced Schottky barrier variation. It further exhibits versatile synaptic functions, such as photonic potentiation/electric depression, pairedpulse facilitation, short/longterm memory, and "learningexperience" behavior. Moreover, the photoplasticity of the memcapacitor can be modulated by varying the frequency of applied AC voltage, thus enabling selfadaptive optical signal detection and mimicry of interestmodulated human visual memory. Therefore, it represents a new paradigm for artificial optoelectronic synapses and opens up opportunities for developing lowpower humanoid optoelectronic devices.

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“…Similar to other MoS2 devices from exfoliated or CVD-grown samples measured under ambient conditions, the response is very slow 3,4,16 . For example, the decay regime of the time-dependent photoresponse curve can be fit by the sum of two exponentials with different time constants, y = A1*exp (-x / τ1) + A2*exp (-x / τ2) + y0 17 . Typical values for τ1 and τ2 are tens and hundreds of seconds, respectively.…”

Section: Manuscript Textmentioning

confidence: 99%

Ambient effects on photogating in MoS₂ photodetectors

et al. 2019

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Atomically thin transition metal dichalcogenides (TMDs) are ideal candidates for ultrathin optoelectronics that is flexible and semitransparent. Photodetectors based on TMDs show remarkable performance, with responsivity and detectivity higher than 10 3 AW -1 and 10 12 Jones, respectively, but they are plagued by response times as slow as several tens of seconds.Although it is well established that gas adsorbates such as water and oxygen create charge traps and significantly increase both the responsivity and the response time, the underlying mechanism is still unclear. Here we study the influence of adsorbates on MoS2 photodetectors under ambient conditions, vacuum and illumination at different wavelengths. We show that, for wavelengths sufficiently short to excite electron-hole pairs in the MoS2, light illumination causes desorption of water and oxygen molecules. The change in the molecular gating provided by the physisorbed molecules is the dominant contribution to the device photoresponse in ambient conditions.

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Electrical transport and persistent photoconductivity in monolayer MoS₂phototransistors

Cited by 201 publications

References 55 publications

Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS₂

Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS₂

An Artificial Optoelectronic Synapse Based on a Photoelectric Memcapacitor

Ambient effects on photogating in MoS₂ photodetectors

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Electrical transport and persistent photoconductivity in monolayer MoS2phototransistors

Cited by 201 publications

References 55 publications

Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS2

Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS2

An Artificial Optoelectronic Synapse Based on a Photoelectric Memcapacitor

Ambient effects on photogating in MoS2 photodetectors

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Electrical transport and persistent photoconductivity in monolayer MoS₂phototransistors

Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS₂

Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS₂

Ambient effects on photogating in MoS₂ photodetectors