UV Broadband Antireflection Coating Using Al2O3, HfO2 and SiO2 Multilayer by Atomic Layer Deposition

Author(s):  
Qing-Yuan Cai ◽  
Ling-Shan Gao ◽  
Hai-Han Luo ◽  
Rui Cong ◽  
Ding-Quan Liu
Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 64 ◽  
Author(s):  
Pallabi Paul ◽  
Kristin Pfeiffer ◽  
Adriana Szeghalmi

Antireflection coatings (ARC) are essential for various optical components including such made of plastics for high volume applications. However, precision coatings on plastics are rather challenging due to typically low adhesion of the coating to the substrate. In this work, optimization of the atomic layer deposition (ALD) processes towards conformal optical thin films of Al2O3, TiO2 and SiO2 on poly(methyl methacrylate) (PMMA) has been carried out and a five-layer ARC is demonstrated. While the uncoated PMMA substrates have a reflectance of nearly 8% in the visible (VIS) spectral range, this is reduced below 1.2% for the spectral range of 420–670 nm by applying a double-side ARC. The total average reflectance is 0.7%. The optimized ALD coatings show a good adhesion to the PMMA substrates even after the climate test. Microscopic analysis on the cross-hatch areas on PMMA after the climate test indicates very good environmental stability of the ALD coatings. These results enable a possible route by ALD to deposit uniform, crack free, adhesive and environmentally durable thin film layers on sensitive thermoplastics like PMMA.


2019 ◽  
Vol 11 (24) ◽  
pp. 21887-21894 ◽  
Author(s):  
Kristin Pfeiffer ◽  
Lilit Ghazaryan ◽  
Ulrike Schulz ◽  
Adriana Szeghalmi

2020 ◽  
Vol 50 (4) ◽  
Author(s):  
Marek Szindler ◽  
Magdalena M. Szindler

Titanium dioxide thin films have been deposited on silicon wafers substrates by an atomic layer deposition (ALD) method. There optical parameters were investigated by spectroscopic ellipsometry and UV/VIS spectroscopy. A material with a refractive index of 2.41 was obtained. Additionally, in a wide spectral range it was possible to reduce the reflection from the silicon surface below 5%. The Raman spectroscopy method was used for structural characterization of anatase TiO2 thin films. Their uniformity and chemical composition are confirmed by a scanning electron microscope (SEM) energy dispersive spectrometer (EDS).


2021 ◽  
Vol 3 (1) ◽  
pp. 59-71
Author(s):  
Degao Wang ◽  
Qing Huang ◽  
Weiqun Shi ◽  
Wei You ◽  
Thomas J. Meyer

2018 ◽  
Author(s):  
Peter George Gordon ◽  
Goran Bacic ◽  
Gregory P. Lopinski ◽  
Sean Thomas Barry

Al-doped ZnO (AZO) is a promising earth-abundant alternative to Sn-doped In<sub>2</sub>O<sub>3</sub> (ITO) as an n-type transparent conductor for electronic and photovoltaic devices; AZO is also more straightforward to deposit by atomic layer deposition (ALD). The workfunction of this material is particularly important for the design of optoelectronic devices. We have deposited AZO films with resistivities as low as 1.1 x 10<sup>-3</sup> Ωcm by ALD using the industry-standard precursors trimethylaluminum (TMA), diethylzinc (DEZ), and water at 200<sup>◦</sup>C. These films were transparent and their elemental compositions showed reasonable agreement with the pulse program ratios. The workfunction of these films was measured using a scanning Kelvin Probe (sKP) to investigate the role of aluminum concentration. In addition, the workfunction of AZO films prepared by two different ALD recipes were compared: a “surface” recipe wherein the TMA was pulsed at the top of each repeating AZO stack, and a interlamellar recipe where the TMA pulse was introduced halfway through the stack. As aluminum doping increases, the surface recipe produces films with a consistently higher workfunction as compared to the interlamellar recipe. The resistivity of the surface recipe films show a minimum at a 1:16 Al:Zn atomic ratio and using an interlamellar recipe, minimum resistivity was seen at 1:19. The film thicknesses were characterized by ellipsometry, chemical composition by EDX, and resistivity by four-point probe.<br>


2019 ◽  
Author(s):  
Jiajia Tao ◽  
Hong-Ping Ma ◽  
Kaiping Yuan ◽  
Yang Gu ◽  
Jianwei Lian ◽  
...  

<div>As a promising oxygen evolution reaction semiconductor, TiO2 has been extensively investigated for solar photoelectrochemical water splitting. Here, a highly efficient and stable strategy for rationally preparing GaON cocatalysts on TiO2 by atomic layer deposition is demonstrated, which we show significantly enhances the</div><div>photoelectrochemical performance compared to TiO2-based photoanodes. For TiO2@20 nm-GaON core-shell nanowires a photocurrent density up to 1.10 mA cm-2 (1.23 V vs RHE) under AM 1.5 G irradiation (100 mW cm-2) has been achieved, which is 14 times higher than that of TiO2 NWs. Furthermore, the oxygen vacancy formation on GaON as well as the band gap matching with TiO2 not only provides more active sites for water oxidation but also enhances light absorption to promote interfacial charge separation and migration. Density functional theory studies of model systems of GaON-modified TiO2 confirm the band gap reduction, high reducibility and ability to activate water. The highly efficient and stable systems of TiO2@GaON core-shell nanowires provide a deeper understanding and universal strategy for enhancing photoelectrochemical performance of photoanodes now available. </div>


2019 ◽  
Author(s):  
Claire Burgess ◽  
Farzad Mardekatani Asl ◽  
Valerio Zardetto ◽  
Herbert Lifka ◽  
Sjoerd Veenstra ◽  
...  

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