Field emission properties of ZnO nanosheet arrays

Naik, Kusha Kumar; Khare, Ruchita T.; Chakravarty, Disha; More, Mahendra A.; Thapa, Ranjit; Late, Dattatray J.; Rout, Chandra Sekhar

doi:10.1063/1.4903271

Cited by 53 publications

(34 citation statements)

References 43 publications

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“…Under UV light, Aldoped ZnO has an ultra-low FE turn-on electric field of 1.3 V μm −1 . After UV light is turned off for 15,25,35,45,55,65,75, and 85 min, the measured turn-on electric field of Al-doped ZnO NWs are 1.8, 1.9, 2.2, 2.5, 2.7, 3.1, 3.1, and 3.2 V μm −1 , respectively. FE performance worsens as the time after UV light is turned off increases.…”

Section: Journal Of the Electrochemical Society 164 (5) B3013-b3028 mentioning

confidence: 99%

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Review—Growth of Al-, Ga-, and In-Doped ZnO Nanostructures via a Low-Temperature Process and Their Application to Field Emission Devices and Ultraviolet Photosensors

Young¹,

Yang²,

Lai³

2016

J. Electrochem. Soc.

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In recent decades, ZnO-based nanostructures have attracted considerable attention because of their various possible morphologies, large surface-to-volume ratios, non-toxicity, easy synthesis, low cost, and excellent physical properties for fabricating highperformance electronic, magnetic, and optoelectronic devices. This review article focuses on recent advances in Al-, Ga-, and In-doped ZnO nanostructures, including a brief overview of the hydrothermal method and aqueous solution methods. Among these strategies, ZnO nanostructures synthesized via the hydrothermal method exhibits distinct advantages, such as low growth temperature, low cost, and large resultant surface area, as well as applicability in fabricating field emission (FE) devices and photosensors. FE devices have gained widespread attention for their applications in flat-panel displays and other electronic devices, such as microwave amplifiers, X-ray tubes, cathode-ray tube monitors, and electron microscopes. FE devices are influenced by interrelated factors, including emitter geometry, crystal structure, conductivity, work function, spatial distribution of emitting centers, and nanostructure density of nanorods. An applied electric field bends the surface barrier to form a triangular barrier, and the excited electrons tunnel easily to generate the emission current. A large number of excited electrons are stored at the tips of nanowires, thereby causing subsequent point discharge that reduces the electric field. ZnO-based ultraviolet (UV) photosensors are frequently used in environmental monitoring, securing space-to-space communication, flame sensing, and chemical biological analysis. ZnO UV photosensors are used to manufacture various structures, such as p-n heterojunction photodiodes, metal-semiconductor-metal photosensors, and Schottky photodiodes. The resistance of pure n-type ZnO nanostructure is high. ZnO nanostructures are commonly doped with other elements. To improve the electrical properties of ZnO nanostructures, donor dopants for ZnO, such as group III elements (Al, Ga, and In), can be used. The optical and electrical properties of fabricated ZnO optoelectronic devices can also be improved by doping with group III elements. Furthermore, as a material with a direct bandgap (3.37 eV), ZnO can easily absorb wavelengths in the UV range. Thus, illumination under UV can enhance the FE capacity of ZnO nanowires. Methods that enhance the performance of field emitters and photosensors are introduced in this review paper. We hope that this review paper can provide a useful reference to those who are interested in ZnO-based field emission devices and photosensors. ZnO-based nanostructures comprise a highly promising key group of II-VI semiconductor materials. ZnO-based nanostructures have numerous advantages, including a wide bandgap of 3.37 eV, a direct bandgap structure at room temperature, a large exciton binding energy of approximately 60 meV, thermal stability at room temperature (significantly higher than that of GaN), non-toxicity, manufactu...

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Section: Journal Of the Electrochemical Society 164 (5) B3013-b3028 mentioning

confidence: 99%

“…The various morphologies of ZnO 1D nanostructures include nanopins, 11 nanorods (NRs), 12 nanotubes, 13 and nanowires (NWs). 14 In addition, 2D ZnO nanosheets (NSs), 15 nanodiscs, 16 and nanoplates have also been fabricated. 17 In general, intrinsic ZnO naturally exhibits the characteristics of an n-type semiconductor.…”

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confidence: 99%

Review—Growth of Al-, Ga-, and In-Doped ZnO Nanostructures via a Low-Temperature Process and Their Application to Field Emission Devices and Ultraviolet Photosensors

Young¹,

Yang²,

Lai³

2016

J. Electrochem. Soc.

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“…In particular, the unique optical, electrical, chemical and ferroelectrical properties and multiple functionalities of ZnO nanorods (NRs) [1][2][3][4] have led many researchers to pursue new synthesis methods with the goal of obtaining high-performance nanoscale devices, 3 such as photovoltaic, [4][5][6] field emitters, 7,8 solar cells, [9][10][11][12] sensors, [13][14][15] photoelectrochemical water splitting, 16 and nanogenerators. [17][18][19] However, the fabrication of practical ZnO NR-based devices is hindered as controlling the density, shape, size, and growth direction of well-defined vertical ZnO NRs with high conductivity remains a significant challenge.…”

Section: Introductionmentioning

confidence: 99%

Homogeneous vertical ZnO nanorod arrays with high conductivity on an in situ Gd nanolayer

et al. 2015

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CitationFlemban TH, Singaravelu V, Sasikala Devi AA, Roqan IS (2015 We demonstrate a novel, one-step, catalyst-free method for the production of size-controlled vertical highly conductive ZnO NR arrays with highly desirable characteristics by pulsed laser deposition using a Gd-doped ZnO target. Our study shows that an in situ transparent and conductive Gd nanolayer (with a uniform thickness of ~1 nm) at the interface between a latticematched (11-20) a-sapphire substrate and ZnO is formed during the deposition. This nanolayer significantly induces relaxation mechanism that controls the dislocation distribution along the growth direction; which consequently improves the formation of homogeneous vertically aligned ZnO NRs. We demonstrate that both the lattice orientation of the substrate and the Gd characteristics are important in enhancing the NR synthesis, and we report precise control of the NR density by changing the oxygen partial pressure. We show that these NRs possess high optical and electrical quality, with a mobility of 177 cm 2 (V.s), which is comparable to the best-reported mobility of ZnO NRs. Therefore, this new and simple method has significant potential for improving the performance of materials used in a wide range of electronic and optoelectronic applications.

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“…In addition, ZNs has advantages in the environmental issue since it has no toxicity, no limitation in the resource, and it could be synthesized by various processes including non vacuum processes such as solution based reaction techniques and ultrasonic spray pyrolysis, in which only relatively low energy is required for the growth process [20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38]. Up to now, several researches have been focusing on the development of cold cathode field emission devices based on ZNs [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]. Recently, we also reported an economically viable synthesis technique of ZNs on a soda-lime glass (SLG) substrate utilizing ultrasonic spray pyrolysis (USP) [22,23,24,25].…”

Section: Introductionmentioning

confidence: 99%

“…Since one dimensional nano-structure such as nanowire has higher morphological aspect ratio than that of a flat surface thin film of the same material, β is significantly increase and it is possible to enhance the electron emission under an applied electric field even at room temperature by utilizing the structural advantage of nanowire. Accordingly, one dimensional material such as ZnO nanowires (abbreviated as ZNs) is know to be one of the promising materials for application in the cold cathode emitter due to its structural property of high aspect ratio [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]. In addition, ZNs has advantages in the environmental issue since it has no toxicity, no limitation in the resource, and it could be synthesized by various processes including non vacuum processes such as solution based reaction techniques and ultrasonic spray pyrolysis, in which only relatively low energy is required for the growth process [20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38].…”

Section: Introductionmentioning

confidence: 99%

Field emission property of ZnO nanowires prepared by ultrasonic spray pyrolysis

Htay

Hashimoto

2015

Superlattices and Microstructures

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The field emission property of cold cathode emitters utilizing the ZnO nanowires with various conditions prepared by ultrasonic spray pyrolysis technique was discussed. It is found that the emission current was enhanced in the emitters having higher aspect ratio as well as smaller sheet resistance. Applying of post-annealing process, utilization of additional Mo back electrode in the cathode, and coating of Mo on the ZnO nanowires resulted in the improvement of the emission current and lowering the threshold voltage. A threshold voltage of about 5.5 V/µm to obtain 1.0 µA/cm 2 was achieved in the sample prepared at the growth temperatures varying continuously from 250• C to 300• C.

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Field emission properties of ZnO nanosheet arrays

Cited by 53 publications

References 43 publications

Review—Growth of Al-, Ga-, and In-Doped ZnO Nanostructures via a Low-Temperature Process and Their Application to Field Emission Devices and Ultraviolet Photosensors

Review—Growth of Al-, Ga-, and In-Doped ZnO Nanostructures via a Low-Temperature Process and Their Application to Field Emission Devices and Ultraviolet Photosensors

Homogeneous vertical ZnO nanorod arrays with high conductivity on an in situ Gd nanolayer

Field emission property of ZnO nanowires prepared by ultrasonic spray pyrolysis

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