Studies on fabrication and characterization of a high-performance Al-doped ZnO/n-Si (1 1 1) heterojunction photodetector

Ismail, Raid A.; Al-Naimi, Ala; Al-Ani, Alaa A

doi:10.1088/0268-1242/23/7/075030

Cited by 40 publications

(21 citation statements)

References 20 publications

(24 reference statements)

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“…The breakdown was observed at À38.6 V, higher than all published results for n-ZnO/p-Si heterojunctions. [20][21][22][23][24] The reverse saturation current is 5.58 Â 10 À7 A, which is between the reported values 2 Â 10 À5 A and 0.17 Â 10 À9 A. 7,8 Under forward bias voltages, the dark current increases exponentially following the equation, I $ exp(aV), which is usually observed in the wide band gap p-n diodes due to a recombination-tunneling mechanism.…”

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confidence: 56%

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: 56%

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 photoresponsibility reached the maximum value of 0.09 A/W at 362 nm and its photo-responsibility decreased gradually to 0.004 A/W with increasing wavelength from 450 nm to 500 nm, indicating visible-blind, UV detectivity. Although the responsibility obtained was higher than the other type p-n junction UV detectors [26][27][28][29], its responsibility was slightly lower than those of the commercial GaN UV detectors ($0.1 A/W) [30]. …”

Section: Photo-responsivity Of Zno Msm Uv Detectormentioning

confidence: 57%

High photo-responsivity ZnO UV detectors fabricated by RF reactive sputtering

Zhang

Hui

2013

Materials Research Bulletin

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“…The¯rst peak is due to the absorption edge of ZnŌ lm while, the second one is ascribed to the absorption edge of bulk silicon. 29,30 Longer annealing time improved the photodetectors responsivity and decreased both the structural defects and the recombination centers. The values of the obtained responsivity are comparable with that of ZnO/Si heterojunction prepared by spray pyrolysis.…”

Section: Resultsmentioning

confidence: 99%

ANNEALING TIME EFFECT ON NANOSTRUCTURED n-ZnO/p-Si HETEROJUNCTION PHOTODETECTOR PERFORMANCE

et al. 2015

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In this work, n-ZnO/p-Si heterojunction photodetectors were prepared by drop casting of ZnO nanoparticles (NPs) on single crystal p-type silicon substrates, followed by (15-60) min; stepannealing at 600 C. Structural, electrical, and optical properties of the ZnO NPs¯lms deposited on quartz substrates were studied as a function of annealing time. X-ray di®raction studies showed a polycrystalline, hexagonal wurtizte nanostructured ZnO with preferential orientation along the (100) plane. Atomic force microscopy measurements showed an average ZnO grain size within the range of 75.9 nm-99.9 nm with a corresponding root mean square (RMS) surface roughness between 0.51 nm-2.16 nm. Dark and under illumination current-voltage (I-V) characteristics of the n-ZnO/ p-Si heterojunction photodetectors showed an improving recti¯cation ratio and a decreasing saturation current at longer annealing time with an ideality factor of 3 obtained at 60 min annealing time. Capacitance-voltage (C-V ) characteristics of heterojunctions were investigated in order to estimate the built-in-voltage and junction type. The photodetectors, fabricated at optimum annealing time, exhibited good linearity characteristics. Maximum sensitivity was obtained when ZnO/Si heterojunctions were annealed at 60 min. Two peaks of response, located at 650 nm and 850 nm, were observed with sensitivities of 0.12-0.19 A/W and 0.18-0.39 A/W, respectively. Detectivity of the photodetectors as function of annealing time was estimated.

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Studies on fabrication and characterization of a high-performance Al-doped ZnO/n-Si (1 1 1) heterojunction photodetector

Cited by 40 publications

References 20 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

High photo-responsivity ZnO UV detectors fabricated by RF reactive sputtering

ANNEALING TIME EFFECT ON NANOSTRUCTURED n-ZnO/p-Si HETEROJUNCTION PHOTODETECTOR PERFORMANCE

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