Sensing devices based on ZnO hexagonal tube-like nanostructures grown on p-GaN heterojunction by wet thermal evaporation

Abdulgafour, H.I.; Hassan, Z.; Yam, F.K.; Chin, C.W.

doi:10.1016/j.tsf.2013.05.091

Cited by 17 publications

(11 citation statements)

References 76 publications

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“…The optical band gap of the pure and M-doped ZnO (M= Cd and Ni) nanorods was obtained from the (αhν) 2 versus hν plot shown in figure 2(b) which was measured using the following equation [23]:…”

Section: Optical Properties Of Pure and M-doped Zno Nanorodsmentioning

confidence: 99%

“…Zinc oxide (ZnO) due to many interesting properties such as direct band gap (3.37eV), relatively large exciton binding energy (60 meV at room temperature) and the possibility of growth in the nanostructure form using many techniques on any substrate makes it a promising candidate for many optoelectronics devices [2][3][4]. Due to the absence of reliable pdoping ZnO, its homojunction diode application has been limited [5].…”

Section: Introductionmentioning

confidence: 99%

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Light emitting diode based on n-Zn0.94M0.06O nanorods/p-GaN (M= Cd and Ni) heterojunction under forward and reverse bias

Echresh

Chey

Shoushtari

et al. 2015

Journal of Luminescence

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In this study, we report on the improvement in the optoelectronic properties of n-ZnO nanorods/p-GaN heterojunction. This was achieved by doping the ZnO with cadmium (Cd) and nickel (Ni). The ZnO and Zn0.94M0.06O nanorods grown hydrothermally on the p-GaN substrate were used to fabricate the light emitting diodes (LEDs). Structural measurement revealed that nanorods with wurtzite structure having a preferential orientation along the (002) c-axis. The UV-vis spectra show that the optical band gap of Zn0.94M0.06O nanorods is decreased in comparison to ZnO nanorods. Electrical measurements of the fabricated LEDs show an obvious rectifying behaviour with low threshold voltage. Electroluminescence (EL) characteristics of LEDs operated at forward and reverse bias were investigated. The EL spectra under forward bias show that doping ZnO nanorods with Cd and Ni led to an intensity enhancement of the broad peak in the visible region while the blue peak originating from the p-GaN substrate remains almost unaffected. The effect of doping was to reduce the valence band offsets and consequently more hole injection has occurred leading to the observed enhancement of the broad band in the visible region. Under reverse bias all heterojunction LEDs show the blue light emission peak originating from the p-GaN substrate.

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Section: Optical Properties Of Pure and M-doped Zno Nanorodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Light emitting diode based on n-Zn0.94M0.06O nanorods/p-GaN (M= Cd and Ni) heterojunction under forward and reverse bias

Echresh

Chey

Shoushtari

et al. 2015

Journal of Luminescence

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show abstract

“…[13][14][15][16][17][18][19][20] Zhu et al [13] deposited undoped nZnO thin films on p-GaN substrates using molecular beam epitaxy (MBE) to form an n-ZnO/p-GaN heterojunction. Under back-illumination conditions, the photodetector shows a UV photoresponse in a narrow spectrum window within 360-390 nm and a low peak responsivity of 1 × 10 −6 A/W at zero bias.…”

Section: Introductionmentioning

confidence: 99%

“…With high sensitivity to UV light, the high density of surface trap states, and a much higher surface area-tovolume ratio, one-dimensional ZnO nanostructures such as nanorods (NRs) or nanowires can improve the properties of photodetectors. [15][16][17][18][19][20] Chen et al reported a UV photodetector based on a ZnO nanowire/p-GaN heterojunction. [17] The heterojunction device in the dark showed a low reverse leakage current and large illuminated current.…”

Section: Introductionmentioning

confidence: 99%

Optoelectronic characteristics of UV photodetector based on GaN/ZnO nanorods p-i-n heterostructures

Zhang

Zhao

Wang

et al. 2015

Electron. Mater. Lett.

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“…The availability of different techniques for growing ZnO in the nanostructure form, its direct wide band gap (3.37 eV), large exciton binding energy (60 meV) and being semiconducting and piezoelectric makes it a promising candidate for many optoelectronics and lasing applications [1][2][3]. Specifically, the light-emitting diodes (LEDs) based on ZnO explored its usability; thus, ZnO-based LEDs are considered as the next-generation LEDs due to their lowcost fabrication process and advanced optical properties [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Effect of NiO intermediate layer on the optical and electrical properties of n-ZnO nanorods/p-GaAs heterojunction

et al. 2015

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ZnO nanorods were grown hydrothermally on bare and NiO-coated p-GaAs substrate to fabricate p-n heterojunctions. The NiO intermediate layer was deposited using thermal evaporation technique. The X-ray diffraction patterns revealed that ZnO nanorods grown on the bare p-GaAs do not have any preferential orientation along the c-axis, but those on the NiO-coated p-GaAs have preferential orientation along the c-axis, i.e. along the (002) direction. The scanning electron microscope images show that the NiO intermediate layer improved the uniformity and the alignment of the ZnO nanorods. Photoluminescence spectra demonstrated that increasing the thickness of NiO intermediate layer leads to improve the optical quality of the ZnO nanorods. Current-voltage characteristics showed that the presence of the NiO intermediate layer leads to increase the threshold voltage and decrease the leakage current of the n-ZnO nanorods/p-GaAs heterojunction. The energy band diagram of heterojunctions drown using Anderson model revealed that the NiO intermediate layer acts as an electron-blocking layer in the ZnO side and at the same time increases the hole injection from the GaAs to the ZnO side. Therefore, most of electron-hole pair recombination could occur at the ZnO site.

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Sensing devices based on ZnO hexagonal tube-like nanostructures grown on p-GaN heterojunction by wet thermal evaporation

Cited by 17 publications

References 76 publications

Light emitting diode based on n-Zn0.94M0.06O nanorods/p-GaN (M= Cd and Ni) heterojunction under forward and reverse bias

Light emitting diode based on n-Zn0.94M0.06O nanorods/p-GaN (M= Cd and Ni) heterojunction under forward and reverse bias

Optoelectronic characteristics of UV photodetector based on GaN/ZnO nanorods p-i-n heterostructures

Effect of NiO intermediate layer on the optical and electrical properties of n-ZnO nanorods/p-GaAs heterojunction

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