Effect of different dopant elements on the properties of ZnO thin films

Nunes, Patrı́cia; Fortunato, Elvira; Tonello, Paulo Sérgio; Fernandes, Francisco Manuel Braz; Vilarinho, Paula M.; Martins, Rodrigo

doi:10.1016/s0042-207x(01)00322-0

Cited by 359 publications

(145 citation statements)

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“…However, the sol-gel technique offers the possibility of preparing a small as well as large-area coating of ZnO thin films at low cost for technological applications. The electrical properties of ZnO film can be modified by heat treatment in H 2 atmosphere or by an appropriate doping process [16]. The doping of impurities such as Al, In, Ga, B resulted in high electrical conductivity [16,17].…”

Section: Introductionmentioning

confidence: 99%

“…The electrical properties of ZnO film can be modified by heat treatment in H 2 atmosphere or by an appropriate doping process [16]. The doping of impurities such as Al, In, Ga, B resulted in high electrical conductivity [16,17]. By the process of doping aluminum to ZnO, free electrons will be released when zinc is replaced by aluminum, so the increase of carrier concentration can improve the conductivity.…”

Section: Introductionmentioning

confidence: 99%

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Al-doped and pure ZnO thin films elaborated by sol-gel spin coating process for optoelectronic applications

Maache

Devers

Chala

2017

Физика И Техника Полупроводников

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Pure and aluminum-doped zinc oxide thin films were grown by spin coating at room temperature. As a starting material, zinc acetate was used. The dopant source was aluminum nitrate; the dopant molar ratio was varied between 1 and 10%. Structural analysis reveals that all films consist of single hexagonal wurtzite phase ZnO, and a preferential orientation along c-axis. They have a homogeneous surface. The measurements show that the films are nanostructured. The transmittance is greater than 75% in the visible region. The band gap energy decreases with the addition of dopant (Al) in prepared thin films and the resistivity decreases significantly.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Al-doped and pure ZnO thin films elaborated by sol-gel spin coating process for optoelectronic applications

Maache

Devers

Chala

2017

Физика И Техника Полупроводников

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“…To get a low resistivity as well as a high transmittance in the visible region, the ZnO is usually doped with group III elements such as aluminum ͑Al͒, indium ͑In͒, gallium ͑Ga͒, and boron ͑B͒. [3][4][5] Doped ZnO has similar electrical and optical properties to indium tin oxide but it is also much cheaper, more temperature stable, and moreover it is nontoxic.…”

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confidence: 99%

“…The electronic structure calculation was performed using the Vienna ab initio simulation package. 15 We employed the projected augmented plane wave 16,17 and the valence configures of 3d 10 4s 2 for Zn, 2s 2 2p 4 for O, and 3s 2 3p 1 for Al were used. Figures 3͑a͒ and 3͑b͒ show the partial density of states ͑DOS͒ for undoped ZnO from the LDA and LDA+ U calculations, respectively.…”

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confidence: 99%

The effect of deposition power on the electrical properties of Al-doped zinc oxide thin films

Chun¹,

Abid

et al. 2010

Applied Physics Letters

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We investigated the effect on the electronic properties of aluminum ͑Al͒-zinc oxide ͑ZnO͒ films by modulating the radio frequency sputtering power. Our experimental results show that increasing the sputtering power increases the Al doping concentration, decreases the resistivity, and also shifts the Zn 2p and O 1s to higher binding energy states. Our local-density approximation ͑LDA͒ and LDA+ U calculations show that the shift in higher binding energy and resistivity decrease are due to an enhancement of the O 2p -Zn 3d coupling and the modification of the Zn 4s -O 2p interaction in ZnO induced by Al doping. © 2010 American Institute of Physics. ͓doi:10.1063/1.3483232͔The zinc oxide ͑ZnO͒ film has received considerable attention recently due to its potential application as a transparent and conductive coating material. 1,2 ZnO is an n-type wide band gap ͑3.3 eV at room temperature͒ semiconductor, and its electrical conductivity dominated by Zn interstitial atoms and oxygen vacancies. The large exciton binding energy ͑BE͒ ͑60 meV͒ and band gap energy of ZnO can be tuned by doping with appropriate elements to enhance its optical and electrical performance. To get a low resistivity as well as a high transmittance in the visible region, the ZnO is usually doped with group III elements such as aluminum ͑Al͒, indium ͑In͒, gallium ͑Ga͒, and boron ͑B͒. 3-5 Doped ZnO has similar electrical and optical properties to indium tin oxide but it is also much cheaper, more temperature stable, and moreover it is nontoxic.In the group III element, Al is considered as the most promising dopant. The highest conductivity values have been found in films with an Al concentration of 2-3 at. %. 6,7 When the ZnO is heavily doped with Al, however, the resistivity increases because of the depletion in carrier concentration due to reduction in the number of oxygen vacancies in Al-ZnO and the neutral impurity scattering due to formation of a sodium ͑Na͒ zeolite structure. 5,7 Many techniques have been employed to prepare Al-ZnO thin films, such as magnetron sputtering, 8 pulsed laser deposition, 9 and chemical deposition. 10 It was found that the properties of Al-ZnO films are strongly dependent upon the preparation conditions such as the deposition methods, chamber pressure, and substrate temperature. 8-10 Furthermore, it was suggested by Cong et al. 11 recently that the Al doping can induce an enhancement of p -d coupling in ZnO. However, no theoretical study has been presented and the origin of the effect of Al doping on electrical properties is still not clear. 12,13 Here, in this letter, we systematically investigated the effect of radio frequency ͑rf͒ sputtering power on the electrical properties of Al-doped ZnO films. Our experiments show that by increasing the sputtering power, the Al doping concentration is increased, which decreases the resistivity and also moves the Zn 2p and O 1s to high BEs energy states. Our local-density approximation ͑LDA͒ and LDA+ U calculations clearly show that the Al doping enhances the p -d coupling and ...

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“…Due to cost increase of indium and the need to have films able to sustain a hydrogen plasma discharge during the deposition process [8], zinc aluminum oxide (ZAO) [9][10][11][12][13] and zinc gallium oxide (ZGO) have been developed as a promising alternative to ITO, since zinc (Zn) is a quite abundant (about 10 3 more than In [14]) and "green" material. Besides that, gallium (Ga) has a better doping efficiency than aluminum (Al), allowing room temperature processing [12,15,16].…”

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confidence: 99%