Concurrent Improvement in Photogain and Speed of a Metal Oxide Nanowire Photodetector through Enhancing Surface Band Bending via Incorporating a Nanoscale Heterojunction

Retamal, José Ramón Durán; Chen, Cheng Ying; Lien, Der Hsien; Huang, Michael R. S.; Lin, Chieh-An; Liu, Chuan Pu; He, Jr Hau

doi:10.1021/ph4001108

Cited by 61 publications

(48 citation statements)

References 37 publications

(60 reference statements)

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“…[60a] In addition, they have reported that the photodetection properties of the device were improved significantly by decorating the ZnO nanowires with Au nanoparticles (Figure c) resulting in an ultralow dark current of 0.13 pA and I photo / I dark ratio of 5 × 10 6 (Figure d). Despite these excellent features, similar to the other ZnO‐based UV photodetectors, these devices exhibited a relatively slow response speed (25 s and 40 s rise time and 10 s and 300s decay time with and without Au decoration) due to the inherent defects, such as oxygen vacancies and zinc interstitials. [60a]…”

Section: Methodsmentioning

confidence: 99%

“…The surface band bending establishes an internal electric field, which spatially separates photogenerated electron–holes leading to suppressed photocarrier recombination and dramatically prolonging carrier life‐times. [2d,3c,21] These effects are particularly prominent in nanocrystalline films, where the surface area is large and the depletion regions may extend throughout the entire film. [1b,2d,3c,9]…”

Section: Photodetection Mechanismmentioning

confidence: 99%

“…Low‐dimensional materials are usually classified into 0D,[19b,20] 1D,[2b,21] and 2D . Quantum dots (QDs), nanotubes, nanowires, nanorods, nanobelts,[22a,27] core/shell structures, nanostructure arrays,[19a,29] epitaxial film, and heterostructures are regarded as the future building blocks of visible‐blind UV photodetectors.…”

Section: Introductionmentioning

confidence: 99%

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Nanoarchitechtonics of Visible‐Blind Ultraviolet Photodetector Materials: Critical Features and Nano‐Microfabrication

Nasiri

Jin

Tricoli

2018

Advanced Optical Materials

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Low-dimensional materials are usually classified into 0D, [19b,20] 1D, [2b,21] and 2D. [22] Quantum dots (QDs), [23] nanotubes, [24] nanowires, [25] nanorods, [18,26] nanobelts, [22a,27] core/ shell structures, [28] nanostructure arrays, [19a,29] epitaxial film, and heterostructures [30] are regarded as the future building blocks of visible-blind UV photodetectors. Compared to traditional thinfilm and bulk materials, low-dimensional nanostructured UV photodetectors are usually characterized by higher responsivity and photoconductivity gain, [1c,31] due to their high surface-areato-volume ratios and the nanoscale confined carrier transport kinetics. [3c,9,25b,32] The large surface-to-volume ratio significantly increases the number of surface trap states that can prolong the photocarrier lifetime by delaying the electron-hole recombination process. [1b,3c,9] In fact, the photoexcited carriers can be trapped by surface trap states and in that case their decay dynamics is dominated by the escape time from the traps. [33] The reduced dimensionality can confine the charge carrier transport path shortening the transit time and reducing recombination events. [3c] Nanostructured wide bandgap UV photodetectors have been produced by several methods, such as magnetron sputtering, [34] pulsed laser deposition, [35] chemical vapor deposition, [36] flame spray pyrolysis, [2d,9,15] and sol-gel. [37] A critical aspect remains how to accurately control the composition and hierarchical arrangement from the atomic scale of surface and bulk defects to the microscale of the active device area. The latter has been shown to be a dominant feature resulting in significant variation in the UV light response of quasi-identical nanomaterials. [9,25b,38] For instance, ZnO nanowires are usually reported to achieve orders of magnitude higher responsivity and detectivity than nanothin ZnO films. Similarly, ultraporous nanoparticle networks have shown thousand folds higher photo to dark-current ratios than more densely arranged ZnO nanoparticle layers resulting in among the highest detectivity reported for such 0D materials. [3c,9,39] Here, we present a comprehensive review of the latest achievements and research directions on the multiscale engineering of wide bandgap semiconductor materials for photodetection of UV light. We will focus on the impact of the nano-to microscale material hierarchy discussing commonalities and discrepancies across materials and morphologies. We will conclude with a review of the rapidly emerging trends and promising strategies for overcoming remaining issues for the engineering of the next generation of miniaturized wide bandgap semiconductors UV photodetectors for wearable and easily deployable devices. Photodetection MechanismWide bandgap semiconductors have been investigated in many recent studies to understand the fundamental process and enhancing the response to the UV light. [9,15,25b,40] The photoresponse characteristics of nanostructured devices are significantly influenced by a number of...

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Section: Methodsmentioning

confidence: 99%

Section: Photodetection Mechanismmentioning

confidence: 99%

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Nanoarchitechtonics of Visible‐Blind Ultraviolet Photodetector Materials: Critical Features and Nano‐Microfabrication

Nasiri

Jin

Tricoli

2018

Advanced Optical Materials

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“…15,16 By choosing, s 1 < s 2 , s 1 (s 2 ) is the shorter (longer) time constant corresponding to the faster (slower) process, which is ascribed to a bulk (surface) dominated process. Therefore, 1/s 2 and 1/s 1 are related to the surface oxygen readsorption/photodesorption rate and the bulk recombination rate, respectively.…”

Section: Effect Of Ultraviolet Illumination On Metal Oxide Resistive mentioning

confidence: 99%

Effect of ultraviolet illumination on metal oxide resistive memory

Retamal

Kang

et al. 2014

Applied Physics Letters

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“…For photodetector applications in particular, SBB enables remarkably high photoconductive gains (G), thanks to the spatial separation of photogenerated electrons and holes in the radial direction of nanowires, and significantly increased carrier lifetimes . The photodetector performance could be further improved under larger degrees of SBB, achieved via local Schottky, or p–n junctions at nanowire surfaces generated by decorating metal or metal oxide nanoparticles . Introducing polycrystallinity into nanowires also has proven beneficial since it creates band‐edge modulation along the nanowire axial direction, enabling high photodetector detectivity ( D *) and reduced dark currents ( I dark ) .…”

Section: Introductionmentioning

confidence: 99%

Extreme Carrier Depletion and Superlinear Photoconductivity in Ultrathin Parallel‐Aligned ZnO Nanowire Array Photodetectors Fabricated by Infiltration Synthesis

Nam

Stein

2017

Advanced Optical Materials

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Ultrathin semiconductor nanowires enable high‐performance chemical sensors and photodetectors, but their synthesis and device integration by standard complementary metal‐oxide‐semiconductor (CMOS)‐compatible processes remain persistent challenges. This work demonstrates fully CMOS‐compatible synthesis and integration of parallel‐aligned polycrystalline ZnO nanowire arrays into ultraviolet photodetectors via infiltration synthesis, material hybridization technique derived from atomic layer deposition. The nanowire photodetector features unique, high device performances originating from extreme charge carrier depletion, achieving photoconductive on–off ratios of >6 decades, blindness to visible light, and ultralow dark currents as low as 1 fA, the lowest reported for nanostructure‐based photoconductive photodetectors. Surprisingly, the low dark current is invariant with increasing number of nanowires and the photodetector shows unusual superlinear photoconductivity, observed for the first time in nanowires, leading to increasing detector responsivity and other parameters for higher incident light powers. Temperature‐dependent carrier concentration and mobility reveal the photoelectrochemical‐thermionic emission process at grain boundaries, responsible for the observed unique photodetector performances and superlinear photoconductivity. The results elucidate fundamental processes responsible for photogain in polycrystalline nanostructures, providing useful guidelines for developing nanostructure‐based detectors and sensors. The developed fully CMOS‐compatible nanowire synthesis and device fabrication methods also have potentials for scalable integration of nanowire sensor devices and circuitries.

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Concurrent Improvement in Photogain and Speed of a Metal Oxide Nanowire Photodetector through Enhancing Surface Band Bending via Incorporating a Nanoscale Heterojunction

Cited by 61 publications

References 37 publications

Nanoarchitechtonics of Visible‐Blind Ultraviolet Photodetector Materials: Critical Features and Nano‐Microfabrication

Nanoarchitechtonics of Visible‐Blind Ultraviolet Photodetector Materials: Critical Features and Nano‐Microfabrication

Effect of ultraviolet illumination on metal oxide resistive memory

Extreme Carrier Depletion and Superlinear Photoconductivity in Ultrathin Parallel‐Aligned ZnO Nanowire Array Photodetectors Fabricated by Infiltration Synthesis

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