Deposition of aluminum-doped zinc oxide thin films for optical applications using rf and dc magnetron sputter deposition

Sivakumar, Kousik; Rossnagel, S. M.

doi:10.1116/1.3425640

Cited by 13 publications

(6 citation statements)

References 19 publications

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“…Average percentage transmission in the visible region of most of the films was in the range of 92-95%. Similar values of transmission in the visible region have been reported [36,37]. Transparency of the film in the visible region is not much effected with films deposited at the higher power and higher substrate temperature, whereas, the absorption of the film increases in the IR region with the increase in the deposition power and substrate heating temperature.…”

Section: Methodssupporting

confidence: 79%

Studies on the effect of hydrogen doping during deposition of Al:ZnO films using RF magnetron sputtering

Shantheyanda¹,

Sundaram²,

Shiradkar³

2012

Materials Science and Engineering: B

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Section: Methodssupporting

confidence: 79%

Studies on the effect of hydrogen doping during deposition of Al:ZnO films using RF magnetron sputtering

Shantheyanda¹,

Sundaram²,

Shiradkar³

2012

Materials Science and Engineering: B

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“…[5] In particular, there is ad istinct lack of printable electrode materials,w ith silver inks currently employed to create the cathode in the bulk of reported printed OPV structures.T hough this approachh as produced single modules with efficiencies exceeding3%a nd has allowed upscaled manufacture to installationsp roducing more than 10 kV by linking upwards of 100 000 cells with ef-ficiencies of 1.5 %i ns eries, [6] moving from thermally evaporated cathode deposition on the small scale to printed cathode depositiono nt he R2R scale remains as ignificant challenge. [7] Sputtering of metal contacts has provent ob easuccessful route for massp roduction of liquid-crystal displays, [8] and presentss ome uniquea dvantages compared to printable cathodes.T he technology is compatible with large-area substrates,c an deposit ar ange of materials including pure metals,a lloys,a nd oxide semiconductors, [9,10] and does not suffer wettabilityi ssues,r esulting in compatibilityw ith aw ide range of device architectures.F urthermore,s puttering…”

Section: Introductionmentioning

confidence: 99%

Roll‐to‐Roll Sputter Coating of Aluminum Cathodes for Large‐Scale Fabrication of Organic Photovoltaic Devices

et al. 2015

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We report the demonstration of sputter‐coated aluminum contacts directly onto P3HT:PCBM organic photovoltaic devices using a R2R process without detrimentally influencing the performance of the devices. The final sputtered devices do not require any protective buffer layers to produce efficient performance. Depth profiling analysis of sputtered films using X‐ray photoelectron spectroscopy (XPS) indicated the presence of a 5–6 nm insulating oxide layer generated at the cathode interface for all sputtering target power densities greater than 1.4 W cm−2. The aluminum penetration into the P3HT:PCBM film was found to be consistent with the depth of this oxide layer, suggesting that aluminum penetration into the organic film is not the primary reason for performance limitations in sputtered devices. Introduction of thermally evaporated aluminum buffer layers prior to deposition of sputtered aluminum cathodes demonstrated that the performance of devices after annealing matched those of reference devices prepared with no sputtering for a buffer layer thickness of only 20 nm. Further analysis of the device J‐‐V curves revealed an S‐shaped kink prior to annealing, indicating that the major reason for the poor performance in sputtered devices was the introduction of a charge extraction barrier at the cathode, which was subsequently removed upon annealing. Rigorous removal of oxygen from the sputtering chamber prior to aluminum deposition onto the P3HT:PCBM active layer was subsequently observed to produce a device with an efficiency close to that of the thermally evaporated reference device without the requirement for evaporated buffer layers. The results presented here highlight a pathway towards an alternative R2R cathode fabrication technique that allows the highly efficient aluminum cathodes employed in small‐scale devices to be transferred onto large‐scale, flexible, and low‐cost R2R printed organic electronic devices.

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“…In other words, the resistivity of GZO films deposited by ALD is sensitive to oxygen during post-annealing, as reported previously. 10 Although the resistivity of GZO deposited on glass increases over 1000 times after post-annealing in oxygen ambient, the crystallinity of GZO films do not show an obvious change observed from X-ray diffraction patterns. 8,[11][12][13] On the other hand, it is found that the resistivity of GZO film can be preserved by passivating the dielectric layer onto the GZO surface.…”

Section: Methodsmentioning

confidence: 94%

Effects of Passivation Layer and Post-Annealing on Ga-Doped ZnO Films Grown by ALD

Chang

Liao

et al. 2013

ECS J. Solid State Sci. Technol.

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In this study, we investigate the effects of passivation layer and post-annealing on the Ga-doped ZnO films grown by thermal-mode atomic layer deposition (TM-ALD) with using H 2 O as oxidant source. The resistivity of ALD-grown GZO deposited on glass and sapphire substrates are 3.9 × 10 −4 -cm and 3.7 × 10 −4 -cm, respectively. The resistivity of GZO films rises irresistibly after post-annealing, especially in oxygen atmosphere. The resistivity also has a significant dependence of substrate and post-annealing ambient. Deposition of a passivation layer is effective to keep the low resistivity and high carrier concentration of GZO during postannealing due to the preservation of the oxygen vacancies. The resistivity could be kept at 6.7 × 10 −4 -cm even by post-annealing at 700 • C. The lowest resistivity of GZO on sapphire substrates is 3.3 × 10 −4 -cm by capping SiO 2 and 3.29 × 10 −4 -cm by capping Al 2 O 3 at 400 • C post-annealing. The maximum transmittance of as-grown GZO increases with post-annealing temperature, especially in the long-wavelength range. In addition, the transmittance in the visible range can be enhanced without red-shift after post-annealing by using a passivation layer.ZnO-based semiconducting materials have been actively investigated by many research groups for applications to blue and ultraviolet light emitters and detectors, due to its wider bandgap (∼3.37 eV) and larger exciton binding energy (∼60 meV) than GaN. Combining the electrical properties changed by controlling doping concentration with the high transmittance makes the ZnO-based transparent conductive oxides (TCOs) attractive for the development of transparent electronics in the visible region. There have been several reports on the growth of high quality n-type ZnO doped with column III elements such as Al, Ga, and In. 1-3 There are many methods to prepare metal-doped ZnO films, such as sputtering, E-beam coating, atomic layer deposition (ALD), 1 chemical vapor deposition (CVD), sol-gel, 4 and spray pyrolysis. 5 There have been some studies on the impurity-doped ZnO deposited by sputtering or the effects of ZnO after post-annealing. [6][7][8] Atomic layer deposition is involved with thermal decomposition, so the chemical reactions occur by thermal energy on the substrate. It provides many advantages including large area deposition, smooth surface morphology, relatively low temperature, high step coverage, and high aspect ratio. In particular, it is possible to grow monolayer in one cycle resulted from the self-limited surface reaction of precursors. Precursors are pulsed individually into the reaction chamber, and the growth rate can be obtained at about one atomic layer per cycle, by pulsing the precursor one by one to separate the chemical reaction in every cycle. In recent years, ZnO-based TCOs deposited by ALD, such as aluminum-doped ZnO (AZO), 1 gallium-doped ZnO (GZO), 9 and indium-doped ZnO (IZO), 3 have been investigated. It is expected to apply the TCO on GaN light-emitting diodes (LEDs) for the improvement of ohmic co...

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Deposition of aluminum-doped zinc oxide thin films for optical applications using rf and dc magnetron sputter deposition

Cited by 13 publications

References 19 publications

Studies on the effect of hydrogen doping during deposition of Al:ZnO films using RF magnetron sputtering

Studies on the effect of hydrogen doping during deposition of Al:ZnO films using RF magnetron sputtering

Roll‐to‐Roll Sputter Coating of Aluminum Cathodes for Large‐Scale Fabrication of Organic Photovoltaic Devices

Effects of Passivation Layer and Post-Annealing on Ga-Doped ZnO Films Grown by ALD

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