Room-Temperature Photodetection Dynamics of Single GaN Nanowires

Гонзалез-Посада, Ф.; Songmuang, R.; Hertog, M. den; Monroy, E.

doi:10.1021/nl2032684

Cited by 148 publications

(175 citation statements)

References 39 publications

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“…The inset is SEM image of the nanobelt device. The electrical transport property of high purity CdS nanobelt is poor at the dark condition, which is consist with the fact CdS nanobelts are highly insulating in the dark with a resistivity above 10 12 Ω and there is low carrier concentration in the high purity semiconductor. 26 There is distinct increasing of photocurrent when the CdS nanobelt was excitation with 405 nm light.…”

Section: Resultsmentioning

confidence: 99%

“…4,8 Up to date, various 1D inorganic materials, such as ZnO, GaN, InAsSb, ZnS, Zn x Cd 1−x Se, ZnTe, CdS, In 2 Te 3 , InSe, have been used to fabrication photodetectors. 4,[9][10][11][12][13] It has been demonstrated that the photoresponse properties of these fabricated detectors are determined critically by a variety of parameters including contact type of device, selected material, as well as the crystalline quality, dimension, surface adsorption and doping. Cadmium sulfide (CdS), as an important semiconductor with direct band gap of 2.47 eV (∼503 nm) at room temperature, has demonstrated interesting physical and chemical properties.…”

Section: Introductionmentioning

confidence: 99%

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Broad spectral response photodetector based on individual tin-doped CdS nanowire

et al. 2014

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High purity and tin-doped 1D CdS micro/nano-structures were synthesized by a convenient thermal evaporation method. SEM, EDS, XRD and TEM were used to examine the morphology, composition, phase structure and crystallinity of as-prepared samples. Raman spectrum was used to confirm tin doped into CdS effectively. The effect of impurity on the photoresponse properties of photodetectors made from these as-prepared pure and tin-doped CdS micro/nano-structures under excitation of light with different wavelength was investigated. Various photoconductive parameters such as responsivity, external quantum efficiency, response time and stability were analyzed to evaluate the advantage of doped nanowires and the feasibility for photodetector application. Comparison with pure CdS nanobelt, the tin-doped CdS nanowires response to broader spectral range while keep the excellect photoconductive parameters. Both trapped state induced by tin impurity and optical whispering gallery mode microcavity effect in the doped CdS nanowires contribute to the broader spectral response. The micro-photoluminescence was used to confirm the whispering gallery mode effect and deep trapped state in the doped CdS nanowires.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Broad spectral response photodetector based on individual tin-doped CdS nanowire

et al. 2014

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“…The illumination intensity was maintained at a low level (<0.05 mW cm -2 ) to minimize any modifi cation of band bending due to screening by free carriers. [ 25 ] Figure 4 (c) shows the result of i-t measurement for a 140 nm membrane with increasing temperature. Fitting the curves with stretched exponential function, [ 24 ] the temperaturedependent time constants were extracted and are plotted in Figure 4 (d) in Arrhenius form.…”

Section: Photoconductance and Surface Barriermentioning

confidence: 99%

Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor

Xiong

Park

Song

et al. 2014

Adv Funct Materials

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We report in this work the fabrication of single crystal GaN nanomembranes, with a thickness as low as 50 nm. Large area (≥5 mm × 5 mm) GaN membranes are produced by electrochemical etching (ECE) with a special high-conductivity sacrifi cial underlayer. Large-area, crackfree transfer of GaN NMs have been performed onto metal, glass, and polymer target substrates. The transport properties of freestanding GaN nanomembranes are analyzed using UV-assisted Hall measurements. The interaction of the carriers with the surface electronic states are investigated by the intensity dependence of the photoconductor gain, and by the temperature-dependent measurements of photocurrent decay. The transport property of GaN NM, down to a thickness of 90 nm, remains very comparable to that from much thicker GaN structures. Enhancement-mode fi eld effect transistors (FETs) have been fabricated and demonstrated on a SiO 2 / Si(001) wafer, suggesting that GaN nanomembranes can be a new candidate for fl exible electronics requiring high power and high-frequency. Results and Discussion Nanomembrane FabricationThe principle of using an ECE process to selectively remove underlying GaN sacrifi cial layers has been described before. [ 12,13 ] Multi-layered GaN structures having nanomembrane layers (50 to 500 nm thick) on top of heavily-doped ( n ≈ 1 × 10 19 cm −3 ) GaN sacrifi cial layers were grown by metal-organic chemical vapor deposition (MOCVD) process on sapphire. To obtain large-area NM within a reasonable time, a periodic array of via holes were created such that the undercut etching can proceeds uniformly around these openings. The via-holes are squares with a dimension of 10 µm and a diagonal periodicity of 25, 50, and 100 µm. These holes were created by Cl-based inductively coupled plasma (ICP) etching to expose the sacrifi cial layer. The photoresist (Shipley S1827) used during the Cl-ICP etching was retained to protect the front surface of the membrane during ECE. The nanomembrane layers became detached from the substrate once the undercut regions around each opening coalesce with the adjacent ones. GaN NMs were cleaned by rinsing sequentially in DI water, acetone and isopropyl-alcohol (IPA). After cleaning, they were transferred on to other substrates Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor Kanglin Xiong , Sung Hyun Park , Jie Song , Ge Yuan , Danti Chen , Benjamin Leung , and Jung Han * Large-area, free-standing and single-crystalline GaN nanomembranes are prepared by electrochemical etching from epitaxial layers. As-prepared nanomembranes are highly resistive but can become electronically active upon optical excitation, with an excellent electron mobility. The interaction of excited carriers with surface states is investigated by intensity-dependent photoconductivity gain and temperature-dependent photocurrent decay. Normally off enhancement-type GaN nanomembrane MOS transistors are demonstrated, suggesting that GaN could be used in fl exible electronics for high power and hig...

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“…In general, nanowires present high photocurrent gain, in the range of 10 5 − 10 8 , with the photocurrent scaling sublinearly with the excitation power, and a time response of the photocurrent in the millisecond range. 14 In comparison with planar devices, almost defect-free semiconductor nanowires open the possibility of exploiting the photoconductive gain while avoiding the deleterious effects of grain boundaries and dislocations on the spectral response. 18 Both ZnO and (Al,Ga)N are promising choices to be used as miniature, visible-blind, ultraviolet (UV) photosensors, [11][12][13][14]16,19 but GaN presents advantages in terms of physical and chemical robustness as well as for controlled doping.…”

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confidence: 99%

UV Photosensing Characteristics of Nanowire-Based GaN/AlN Superlattices

et al. 2016

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We have characterized the photodetection capabilities of single GaN nanowires incorporating 20 periods of AlN/GaN:Ge axial heterostructures enveloped in an AlN shell. Transmission electron microscopy confirms the absence of an additional GaN shell around the heterostructures. In the absence of a surface conduction channel, the incorporation of the heterostructure leads to a decrease of the dark current and an increase of the photosensitivity. A significant dispersion in the magnitude of dark currents for different single nanowires is attributed to the coalescence of nanowires with displaced nanodisks, reducing the effective length of the heterostructure. A larger number of active nanodisks and AlN barriers in the current path results in lower dark current and higher photosensitivity, and improves the sensitivity of the nanowire to variations in the illumination intensity (improved linearity). Additionally, we observe a persistence of the photocurrent, which is attributed to a change of the resistance of the overall structure, particularly the GaN stem and cap sections. In consequence, the time response is rather independent of the dark current.

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Room-Temperature Photodetection Dynamics of Single GaN Nanowires

Cited by 148 publications

References 39 publications

Broad spectral response photodetector based on individual tin-doped CdS nanowire

Broad spectral response photodetector based on individual tin-doped CdS nanowire

Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor

UV Photosensing Characteristics of Nanowire-Based GaN/AlN Superlattices

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