Charge-Separation Kinetics of Photoexcited Oxygen Vacancies in ZnO Nanowire Field-Effect Transistors

Lu, Michael S.-C.; Chen, Chieh-Wei; Lu, Ming-Yen

doi:10.1103/physrevapplied.6.054018

Cited by 20 publications

(9 citation statements)

References 57 publications

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“…47 Lu et al reported a positive correlation between the electric field and the charge-separation behavior of photoexcited electrons and ionized oxygen vacancies (V + O /V 2+ O ) in a ZnO field-effect transistor. 48 Analogously, in this work, a greater probability of a higher charge-separation and more photoexcited electrons in the ZTO channel was attained by applying a light-bias programming V G,prog. = −40 V process with light illumination.…”

Section: Resultssupporting

confidence: 51%

“…These results show that the charge-separation probability of the photoexcited electrons and V 2+ O is increased during the light-bias application, resulting in more photoexcited carriers in the ZTO than that under the light illumination. 47,48 Moreover, V 2+ O in the ZTO are driven to accumulate at the interface between the ZTO and Au NP with the application of V G,prog. = −40 V. The Schottky barrier width, which depends on the density of V 2+ O at the interface and determined the tunneling current, plays a key role for the memory performance.…”

Section: Resultsmentioning

confidence: 99%

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A multilevel nonvolatile visible light photomemory based on charge transfer in conformal zinc–tin oxide/Au nanoparticle heterostructures

et al. 2022

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Section: Resultssupporting

confidence: 51%

Section: Resultsmentioning

confidence: 99%

A multilevel nonvolatile visible light photomemory based on charge transfer in conformal zinc–tin oxide/Au nanoparticle heterostructures

et al. 2022

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“…[4][5][6] The latter ZnO-based heterostructure is one of the few oxides where the quantum Hall effect (QHE) 4 and the fractional quantum Hall effect (FQHE) 6 have been detected. On the other hand, ZnO is an appealing wide-bandgap semiconductor for optoelectronics 7 with an energy gap of E G ¼ 3.36 eV and a large exciton binding energy ('60 meV). 8 Moreover, the optoelectronic properties of ZnO are highly sensitive to adsorbed species on its surface.…”

mentioning

confidence: 99%

Franz-Keldysh effect in epitaxial ZnO thin films

Bridoux

Villafuerte

Ferreyra

et al. 2018

Applied Physics Letters

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Photoconductance spectroscopy has been studied in epitaxial ZnO thin films with different thicknesses that range between 136 and 21 nm. We report a systematic decrease in photoconductivity and a red shift in band edge photoconductance spectra when the thickness is reduced. For thinner films, it is found that the effective energy gap value diminishes. By time dependent photoconductivity measurements, we found an enhanced contribution of the slow relaxation times for thicker films. These effects are interpreted in terms of a band-bending contribution where the Franz-Keldysh effect and the polarization of ZnO play a major role in thinner films.

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“…34 Analogously, in this work, a greater probability of separation between the photoexcited electrons and ionized oxygen vacancies (V o 2+ /V o + ) in oxide semiconductors is reasoned as the external increases. 35 Accordingly, the overlapping of the voltage pulse and light pulse reinforces the gate bias-enhanced charge separation effect and contributes more photoexcited electrons in the channel, leading to the amplification of drain current when |Δt| gets close to 0 s.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Temporal Modulation and Synergistic Current Response of Zinc-Tin Oxide/Gold Nanoparticle Phototransistors Triggered by an Electrical–Optical Hybrid Pulse

Shih

Lin

Chen

et al. 2022

ACS Appl. Electron. Mater.

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The development of neuromorphic computation has made enormous progress in time-series forecasting, non-structural visual data, and pattern recognition. Regarding hardware implementation, the temporal response of multiple inputs and processing-in-sensor techniques are especially crucial for the implemented sensing devices to manage massive data with nonlinear processing. In this study, we demonstrated an extensive conductance modulation of a lightsensitive zinc-tin oxide (ZTO) phototransistor in responding to an electrical− optical hybrid composed of a negative gate voltage pulse and 405 nm light pulse. By precisely controlling the lead time (Δt, −5 s ≤ Δt ≤ 5 s) of light spike in the hybrid pulse, a synergistic current amplification effect is revealed when the gate voltage spike and 405 nm light spike are fully or partially overlapped. When the phototransistor is embedded with gold nanoparticles (ZTO/Au NP phototransistor), the synergistic current amplification effect is even more significant. With Δt = 0 s, the fully overlain light/voltage hybrid pulse-induced current changes (ΔI h ) on ZTO and ZTO/Au NP phototransistors are 13-and 16-fold, respectively, of the value obtained by summing up the current induced by the individual pulse. The current amplification factor is spike-timing-dependent, and it is a multifaceted phenomenon correlating with the gate bias-enhanced electron detrapping and carrier generation in ZTO under light illumination, the hot electrons contributed from Au NPs, and the current retention that arise from the prior pulse. With the electrical−optical synergistic effect and manifold temporal response, both phototransistors show the potential to be implemented for data processing in sensor networks.

show abstract

Charge-Separation Kinetics of Photoexcited Oxygen Vacancies in ZnO Nanowire Field-Effect Transistors

Cited by 20 publications

References 57 publications

A multilevel nonvolatile visible light photomemory based on charge transfer in conformal zinc–tin oxide/Au nanoparticle heterostructures

A multilevel nonvolatile visible light photomemory based on charge transfer in conformal zinc–tin oxide/Au nanoparticle heterostructures

Franz-Keldysh effect in epitaxial ZnO thin films

Temporal Modulation and Synergistic Current Response of Zinc-Tin Oxide/Gold Nanoparticle Phototransistors Triggered by an Electrical–Optical Hybrid Pulse

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