Ultraviolet-enhanced photodiode employing n-ZnO/p-Si structure

Jeong, I. S.; Kim, Jae-Hoon; Im, Seongil

doi:10.1063/1.1616663

Cited by 376 publications

(183 citation statements)

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“…According to the best of our knowledge, this responsivity is at least 30 times higher than most of the published results. 6,[26][27][28][29] However, this is lower than the responsivity of n-ZnO/p-Si heterojunction photodiode fabricated using DC magnetron sputtering method reported by Kosyachenko et al, which can reach to 210 A/W at 390 nm with À5 V bias. 30 Under reverse bias conditions, a monotonous increase of the photoresponsivity with increasing wavelength was observed in the visible range (450-800 nm).…”

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confidence: 64%

“…Due to the limited penetration depth of UV light (36-40 nm) in ZnO, most of the UV light is absorbed by ZnO NWs. 27 When reverse biased, the UV generated EPH can easily move across the interfacial region and be collected by the contacts. However, under forward bias conditions, the UV generated electrons in the ZnO NWs region will move toward the p-Si side and therefore need to pass through a small potential barrier in the interfacial region.…”

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confidence: 99%

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Heterojunction photodiode fabricated from hydrogen treated ZnO nanowires grown on p-silicon substrate

Shao

Lian

et al. 2012

Applied Physics Letters

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A heterojunction photodiode was fabricated from ZnO nanowires (NWs) grown on a p-type Si (100) substrate using a hydrothermal method. Post growth hydrogen treatment was used to improve the conductivity of the ZnO NWs. The heterojunction photodiode showed diode characteristics with low reverse saturation current (5.58 Â 10 À7 A), relatively fast transient response, and high responsivity (22 A/W at 363 nm). Experiments show that the photoresponsivity of the photodiode is dependent on the polarity of the voltages. The photoresponsivity of the device was discussed in terms of the band diagrams of the heterojunction and the carrier diffusion process. Semiconductor nanowires (NWs) have garnered extensive research interests due to their unique optical and electrical properties. 1,2 In particular, ZnO NWs are promising for optoelectronic applications including ultraviolet (UV) lightemitting diodes (LED), UV laser diodes, and UV photodetectors for their wide band gap (3.37 eV), large exciton binding energy 60 meV, and high photoconductive gain. [3][4][5] The development of a ZnO pn junction has been limited by the difficulty of growing p-type ZnO. However, heterojunctions with ZnO NWs have been developed with p-type substrates including silicon. [6][7][8][9] The traditional bottom up approach is often employed which causes poor conductivity and high density of surface defects. Post growth hydrogen treatment is a simple and efficient method for the conductivity enhancement, which is intensively investigated both theoretically and experimentally. [10][11][12][13][14] The conductivity of ZnO could be enhanced by up to three orders of magnitude without significant changes in the structure and crystal orientation of the wurtzite type ZnO nanostructures. 12 The conductivity enhancement could be attributed to the introduction of shallow donor states such as the VO-H complex and the hydrogen interstitial. 15,16 Also, the passivation effect on the defects could reduce carrier scattering centers and hence has the potential to increase the electron mobility. 17 In this study, heterojunction photodiode was fabricated based on highly vertically aligned hydrogen treated ZnO NWs grown on top of p-Si substrate through hydrothermal method. A similar growth method has been reported by Ghosh and Basak for quasialigned ZnO NWs/p-Si heterojunction photodiode. 8 The heterojunction photodiode in this work shows a low reverse saturation current and relatively fast time response. The photoresponsivity spectra of the device in the UV and visible regions depend on the polarity of the applied voltages, which is explained in terms of energy band structure and carriers transportation mechanism inside the heterojunction structure.All chemical reagents were purchased from SigmaAldrich and used without further purification. Ammonium hydroxide (28 wt. %) was added dropwise into 0.1M zinc chloride solution until the pH is 10-11 and the solution was clear. Subsequently, the transparent solution was transferred to a Teflon-lined autoclave (Parr, USA) and th...

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confidence: 64%

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confidence: 99%

Heterojunction photodiode fabricated from hydrogen treated ZnO nanowires grown on p-silicon substrate

Shao

Lian

et al. 2012

Applied Physics Letters

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“…The effect is attributed to an optical excitation of free electrons from the Al-defect levels positioned ~ 80 meV below the conduction band. The photoconduction response of ZnO can be also improved by engineering heterojunctions with other semiconductors or high electronegativity metals such as Pt, Pd, etc., which are known to form Schottky-type junctions at the metal-ZnO interface (Jeong et al 2003;Heo et al 2004;Keem et al 2004;Yong 2006). However, the results of more recent studies performed by us indicate additional possibilities of achieving strong sub-band-gap sensitivity based on avalanche-type photocarrier multiplication effects by intentionally introducing transition metal (TM) centers such as Cu within the core regions of ZnO.…”

Section: Sensing Light With Zno Nanowiresmentioning

confidence: 82%

Transition Metal-Doped ZnO Nanowires: En Route Towards Multi-colour Light Sensing and Emission Applications

Kouklin¹,

Omari²,

Gupta³

2010

Nanowires Science and Technology

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368and strength of the chemical bonds of wide-band gap semiconductors, photodetectors engineered based on most of metal-oxides can withstand highly elevated T and hostile environments. Despite the fact that carrier mobilities are much smaller in cases of metal oxides compared with those of many conventional semiconductors, owing to the drastically increased dielectric strength of metal oxides, much larger carrier velocities can be readily achieved by applying much higher electric fields/device biases. The property remains critical for reducing the photogenerated carrier transit time and thus improving gain characteristics of the photodetectors. Advances in nanofabrication methodologies now allow growing many metal-oxide nanowires, including in ZnO as dislocation-free, highly faceted single crystals, which according to the above-made discussion show significant promise for diverse nanophotodetector device as well as light-emission applications. At the same time, compared to cSi, ZnO nanowires typically exhibit a very limited intrinsic sensitivity to visible and infrared radiation, whereas the sensitivity to short-wavelength photons also tends to be reduced as a result of their small diameter and relative increase in the number of the surface defect states. In this chapter, we provide a brief review on the progress in engineering highresponsitivity ZnO nanowire photodetectors operating in an extended, i.e., ultravioletvisible spectral range. Particular attention is paid to the use and role of transition metal dopants to enhance the light sensitivity of ZnO nanowires/nanorods grown by seeded vapor-transport methods. Detailed consideration is given to several key aspects pertaining to the transport, photoconduction, and time-response characteristics of two-terminal metalsemiconductor-metal nano-photodetectors operating at both pre-avalanche and avalanche regimes. This review might be important to scientists working in with high-sensitivity and multispectral oxide-based nano-photodetectors, optical switches, and sensors.

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“…For the n-ZnO/p-Si heterojunction solar cells, the solar light can be efficiently collected owing to the wide band gap of ZnO (Eg=3.3 eV). That is, high energy photons can be absorbed in the ZnO region, while low energy photons that are transmitted through the ZnO layer can be absorbed in the depletion region of p-Si [3]. In addition, ZnO film has good electrical and optical properties with low price and non-toxicity [4].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Photo Current in n-ZnO/p-Si Diode Via Embedded Ag Nanoparticles for the Solar Cell Application

Ko¹,

Yun²,

Jeong³

et al. 2015

JSTS:Journal of Semiconductor Technology and Science

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Abstract-In this study, an n-ZnO/p-Si heterojunction diode with embedded Ag nanoparticles was fabricated to investigate the possible improvement of light trapping via the surface plasmon resonance effect for solar cell applications. The Ag nanoparticles were fabricated by the physical sputtering method. The acquired current-voltage curves and optical absorption spectra demonstrated that the application of Ag nanoparticles in the n-ZnO/p-Si interface increased the photo current, particularly in specific wavelength regions. The results indicate that the enhancement of the photo current was caused by the surface plasmon resonance effect generated by the Ag nanoparticles. In addition, minority carrier lifetime measurements showed that the recombination losses caused by the Ag nanoparticles were negligible. These results suggest that the embedding of Ag nanoparticles is a powerful method to improve the performance of n-ZnO/p-Si heterojunction solar cells.

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Ultraviolet-enhanced photodiode employing n-ZnO/p-Si structure

Cited by 376 publications

References 10 publications

Heterojunction photodiode fabricated from hydrogen treated ZnO nanowires grown on p-silicon substrate

Heterojunction photodiode fabricated from hydrogen treated ZnO nanowires grown on p-silicon substrate

Transition Metal-Doped ZnO Nanowires: En Route Towards Multi-colour Light Sensing and Emission Applications

Enhanced Photo Current in n-ZnO/p-Si Diode Via Embedded Ag Nanoparticles for the Solar Cell Application

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