Ultrahigh photocurrent gain in m-axial GaN nanowires

Chen, Reui-San; Chen, Hsin‐Yi; Lu, Chien-Yao; Chen, Kuei‐Hsien; Chen, Chin-Pei; Chen, Li‐Chyong; Yang, Yao‐Joe

doi:10.1063/1.2817595

Cited by 142 publications

(106 citation statements)

References 19 publications

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“…Thus, crystallographic orientation and surface polarity is seen to play an important role in deciding the performance of the photodetectors by modifying the metal-semiconductor contact. 13 In this work, we optimized good quality nonpolar (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) a-GaN grown on (1-102) r-plane sapphire substrate by changing the growth conditions. The photodetector is fabricated on the best grown film and its performance was compared with photodetector grown on conventional (0 0 0 2) c-plane axis.…”

Section: Introductionmentioning

confidence: 99%

Enhanced UV detection by non-polar epitaxial GaN films

et al. 2015

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Nonpolar a-GaN (11-20) epilayers were grown on r-plane (1-102) sapphire substrates using plasma assisted molecular beam epitaxy. High resolution x-ray diffractometer confirmed the orientation of the grown film. Effect of the Ga/N ratio on the morphology and strain of a-GaN epilayers was compared and the best condition was obtained for the nitrogen flow of 1 sccm. Atomic force microscopy was used to analyze the surface morphology while the strain in the film was quantitatively measured using Raman spectroscopy and qualitatively analyzed by reciprocal space mapping technique. UV photo response of a-GaN film was measured after fabricating a metal-semiconductor-metal structure over the film with gold metal. The external quantum efficiency of the photodetectors fabricated in the (0002) polar and (11-20) nonpolar growth directions were compared in terms of responsivity and nonpolar GaN showed the best sensitivity at the cost of comparatively slow response time.

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Section: Introductionmentioning

confidence: 99%

Enhanced UV detection by non-polar epitaxial GaN films

et al. 2015

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“…The PC gain of the device without the assistance of magnetic field can reach up to 8800 due to more surface defects than that of the annealed NW device. 38 With the effect of the magnetized Ni electrodes, the PC gain can be as high as 4.7 Â 10 4 , and the highest enhancement factor can also have a large value of 3000%. This result demonstrates that the ultrahigh gain phenomenon can also be obtained even if the pristine NWs have a higher state of surface defects.…”

Section: Resultsmentioning

confidence: 99%

Ultrahigh-gain single SnO2 nanowire photodetectors made with ferromagnetic nickel electrodes

Weng

Chen

et al. 2012

NPG Asia Mater

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We report the first attempt at magnetic manipulation of the photoresponse in a one-dimensional device in which a highly sensitive ultraviolet photodetector, composed of tin dioxide nanowire (SnO 2 NW) and ferromagnetic nickel (Ni) electrodes, has been fabricated and characterized. Surprisingly, as the Ni electrodes were magnetized, the photocurrent gain was greatly enhanced by up to 20 times, which is far beyond all of the previously reported enhancement factors for functionalized NW photodetectors. The underlying mechanism enabling the enhanced gain is attributed to both oxygen molecules adsorbed and surface band-bending effects due to the migration of electrons to the surface of SnO 2 NW caused by the magnetic field of ferromagnetic electrodes. The novel approach presented here can provide a new route for the creation of highly efficient optoelectronic devices based on the coupling between ferromagnetic materials and nanostructured semiconductors.

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“…5,6 Meanwhile, NWs possess a large surface-to-volume ratio while maintaining the direct conduction pathway, which is quite unique and can be advantageous as building blocks for next generation devices. As reported earlier, the surface dominates and significantly impacts the photoconductivity, 7,8 mechanical, 9 and electromechanical 10 properties of GaN NWs at a scale far beyond the quantum confinement regime. The direct conduction pathway is essential for the NW-based field-effect-transistor sensors as they can serve as both the signal transducer and the transmitter.…”

Section: Introductionmentioning

confidence: 88%

Optical properties of functionalized GaN nanowires

Hsu

Ganguly

Chen

et al. 2011

Journal of Applied Physics

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The evolution of the optical properties of GaN nanowires (NWs) with respect to a sequence of surface functionalization processes is reported; from pristine hydroxylated to finally, 3-mercaptopropyltrimethoxysilane (MPTMS) functionalized GaN NWs. Photoluminescence, Raman, stationary, and time-resolved photoluminescence measurements were applied to investigate the GaN NWs with different surface conditions. A documented surface passivation effect of the GaN NWs induced by the MPTMS functionalization is determined based on our characterization results. A hypothesis associated with the surface band bending and the defect levels near the band edges is proposed to explain the observed experimental results.

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Ultrahigh photocurrent gain in m-axial GaN nanowires

Cited by 142 publications

References 19 publications

Enhanced UV detection by non-polar epitaxial GaN films

Enhanced UV detection by non-polar epitaxial GaN films

Ultrahigh-gain single SnO2 nanowire photodetectors made with ferromagnetic nickel electrodes

Optical properties of functionalized GaN nanowires

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