Transmission/absorption measurements for in situ monitoring of transparent conducting Ga:ZnO films grown via aqueous methods

Kevin, Moe; Ho, Ghim Wei

doi:10.1039/c3ta12461d

Cited by 11 publications

(7 citation statements)

References 17 publications

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“…Recent reports on conductive ZnO thin films prepared via CBD have indicated progress toward achieving this goal . In those studies, however, the TCEs were prepared using aliovalent doping (Al or Ga) and often required a postdeposition annealing step at elevated temperatures.…”

Section: Introductionmentioning

confidence: 99%

Flash‐Assisted Processing of Highly Conductive Zinc Oxide Electrodes from Water

Gaspera

Kennedy

Embden

et al. 2015

Adv Funct Materials

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Fabricating high‐quality transparent conductors using inexpensive and industrially viable techniques is a major challenge toward developing low cost optoelectronic devices such as solar cells, light emitting diodes, and touch panel displays. In this work, highly transparent and conductive ZnO thin films are prepared from a low‐temperature, aqueous deposition method through the careful control of the reaction chemistry. A robotic synthetic platform is used to explore the wide parameter space of a chemical bath system that uses only cheap and earth abundant chemicals for thin film deposition. As‐deposited films are found to be highly resistive, however, through exposure to several millisecond pulses of high‐intensity, broadband light, intrinsically doped ZnO films with sheet resistances as low as 40 Ω □−1 can be readily prepared. Such values are comparable with state‐of‐the‐art‐doped transparent conducting oxides. The mild processing conditions (<150 °C) of the ZnO electrodes also enable their deposition on temperature sensitive substrates such as PET, paving the way for their use in various flexible optoelectronic devices. Proof‐of‐concept light emitting devices employing ZnO as a transparent electrode are presented.

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Section: Introductionmentioning

confidence: 99%

Flash‐Assisted Processing of Highly Conductive Zinc Oxide Electrodes from Water

Gaspera

Kennedy

Embden

et al. 2015

Adv Funct Materials

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“…Table 1 Summary of the films' properties, including the dopant incorporation in the material, the sample thickness, the average grain size, the position of the (002) reflection, the optical bandgap E G , the Urbach energy E U , the optical carrier concentration N opt and mobility l opt , the optical resistivity q opt and the electrical resistivity q 4p for which the deposition time was extended where necessary, in order to obtain comparable film thicknesses in the range of 2.7 lm. The reason for this was to be able to compare the electrical properties of the different doped films, as the resistivity of materials grown by this technique is known to have a thickness dependence [21]. However, for the highest Al doping, it was not possible to grow a film thicker than 2.2 lm even after prolonging the deposition time from the typical 30 to 90 min (using a single bath).…”

Section: Dopant Incorporationmentioning

confidence: 99%

Comparison of chemical bath-deposited ZnO films doped with Al, Ga and In

et al. 2017

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A comparative study is presented on chemical bath-deposited ZnO films, doped with the group-13 metals Al, Ga and In. The study reveals marked differences in dopant incorporation in the films, which increases in the order: In, Al and Ga. The presence of dopant in the solution induces significant modifications in the deposition rate, which varies between 110 and 40 nm min -1 . All films are (002)-textured, whereas the lattice stress evolution with the dopant type and concentration suggests that Ga has the highest degree of substitutional incorporation in Zn sites. The average visible transmittance is higher than 80%, while the infrared reflectivity depends on the free carrier density in the films, which is the lowest for undoped ZnO and increases in the order: In-, Al-and Ga-doped ZnO. Optical measurements also yield an inverse correlation between carrier density and mobility. Doping enlarges the bandgap, as well as the Urbach energy that is related to the films' disorder. The lowest electrical resistivity, measured by fourpoint probe, is 1.7 9 10 -2 X cm and is obtained for In-doped films after being exposed to ultraviolet light. Ga-doped films are found to exhibit the highest stability of the conductivity upon ultraviolet exposure.

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“…For this reason, a ZnO precursor was favored over Zn(NO 3 ) 2 in this study. It is worth mentioning that through careful adjustment of pH, ammonia concentration, and bath temperature, high growth rates can also be achieved using Zn(NO 3 ) 2 as shown in the comprehensive study of Kevin and Ho .…”

Section: Resultsmentioning

confidence: 99%

Doping strategies for highly conductive Al-doped ZnO films grown from aqueous solution

Fuchs

Hagendorfer

Romanyuk

et al. 2014

Phys. Status Solidi A

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Aluminum‐doped zinc oxide (AZO) thin films are prepared by a low temperature (100 °C) aqueous solution deposition method with a subsequent UV post‐deposition treatment at 140 °C. Film growth is governed by the retrograde solubility of zinc–ammine complexes at basic conditions (pH 11.4). Aluminum was introduced into the film as a dopant by co‐precipitation, either using an aluminum metal foil or aluminum nitrate as a precursor. As the presence of Al ions in the solution influences the film morphology as well as the opto‐electronic properties, different profiles of the dopant supply were examined and optimized with respect to the optical and electrical properties of the AZO layer. It was found that independent of the chosen aluminum precursor a linearly increasing dopant concentration in the solution is favorable for achieving dense, highly transparent (<8% absorption between 400 and 900 nm) AZO thin films with a lowest resistivity of 3.4 × 10−3 Ω cm.

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Transmission/absorption measurements for in situ monitoring of transparent conducting Ga:ZnO films grown via aqueous methods

Cited by 11 publications

References 17 publications

Flash‐Assisted Processing of Highly Conductive Zinc Oxide Electrodes from Water

Flash‐Assisted Processing of Highly Conductive Zinc Oxide Electrodes from Water

Comparison of chemical bath-deposited ZnO films doped with Al, Ga and In

Doping strategies for highly conductive Al-doped ZnO films grown from aqueous solution

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