Synthesis and enhanced photocatalytic performance of 0D/2D CuO/tourmaline composite photocatalysts

• Changqiang Yu,
• Min Wen,
• Zhen Tong,
• Shuhua Li,
• Yanhong Yin,
• Xianbin Liu,
• Yesheng Li,
• Tongxiang Liang,
• Ziping Wu and
• Dionysios D. Dionysiou

Beilstein J. Nanotechnol. 2020, 11, 407–416, doi:10.3762/bjnano.11.31

• the treatment of organic contaminants in wastewater is in urgent need owing to the deterioration of the ecological environment [1]. Metal oxides, such as ZnO [2], TiO2 [3], Fe2O3 [4], and CuO [5], have been demonstrated to be promising photocatalysts. In particular, the band gap energy (Eg) of the p

• construction of CuO-based heterostructures (e.g., 0D/2D CuO/TiO2, 0D/3D CuO/ZnO, 2D/2D CuO/Fe2O3, 0D/2D CuO/C3N4, 2D/0D CuO/Ag3PO4) [6][12][15][16][17] and the dispersion of CuO on supporting materials (e.g., graphene, carbon nanotube) [7][18] are considered to be the most effective ways to address these

Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment

• Xiaomei Zeng,
• Vasiliy Pelenovich,
• Bin Xing,
• Rakhim Rakhimov,
• Wenbin Zuo,
• Alexander Tolstogouzov,
• Chuansheng Liu,
• Dejun Fu and
• Xiangheng Xiao

Beilstein J. Nanotechnol. 2020, 11, 383–390, doi:10.3762/bjnano.11.29

• used to irradiate single crystal ZnO substrates and nanorods to fabricate self-assembled surface nanoripple arrays. The ripple formation is observed when the incidence angle of the cluster beam is in the range of 30–70°. The influence of incidence angle, accelerating voltage, and fluence on the ripple

• parallel steps or ribs. The more ordered ripple formation on nanorods can be associated with the confinement of the nanorod facets in comparison with the quasi-infinite surface of the flat substrates. Keywords: cluster ion bombardment; gas cluster ion beam; surface ripples; ZnO nanorods; Introduction The

• ZnO nanorods irradiated by GCIB. The modification effects of the gas cluster ion beams on the nanostructured targets at different incidence angles, accelerating voltages, and ion fluences are studied. The differences between nanoripple formation on planar ZnO substrates and on nanorods are also

Synthesis and acetone sensing properties of ZnFe₂O₄/rGO gas sensors

• Kaidi Wu,
• Yifan Luo,
• Ying Li and
• Chao Zhang

Beilstein J. Nanotechnol. 2019, 10, 2516–2526, doi:10.3762/bjnano.10.242

• concentration. Due to their excellent properties and cost efficiency, gas sensors based on metal oxide semiconductors, such as ZnO [5], SnO2 [6], WO3 [7], TiO2 [8], Er-SnO2 [9], Au-In2O3 [10], GO-WO3 [11] and Ni-SnO2/G [12] have been widely studied until now. However, their sensing properties regarding low

• morphology [16]. Some researchers also found that Ag-activated hollow spheres of ZnFe2O4 exhibited an excellent acetone gas-sensing performance at 175 °C [17]. Moreover, ZnFe2O4/ZnO composites showed an excellent response and recovery performance, which was attributed to their nanostructure and synergistic

• (10 ppb) [29]. ZnO1−x/rGO composites with 2 wt % rGO had enhanced gas sensing properties compared with pure ZnO, as indicated by an enhanced sensitivity and an improved response/recovery speed [30]. It has been proved that coupling or compounding metal oxides with graphene enhances the electronic

Semitransparent Sb₂S₃ thin film solar cells by ultrasonic spray pyrolysis for use in solar windows

• Jako S. Eensalu,
• Atanas Katerski,
• Erki Kärber,
• Lothar Weinhardt,
• Monika Blum,
• Clemens Heske,
• Wanli Yang,
• Ilona Oja Acik and
• Malle Krunks

Beilstein J. Nanotechnol. 2019, 10, 2396–2409, doi:10.3762/bjnano.10.230

• nontransparent 125 nm Ag back contact [21]. TiO2 is the most commonly used electron transport material (ETM) in Sb2S3 solar cells [18][25][26][27][28][29][30][31][32]. SnO2 and ZnO have also been employed as the planar ETM, with varying success [33][34]. Conjugated polymers, e.g., P3HT, Spiro-OMeTAD (2,2',7,7

Integration of sharp silicon nitride tips into high-speed SU8 cantilevers in a batch fabrication process

• Nahid Hosseini,
• Matthias Neuenschwander,
• Oliver Peric,
• Santiago H. Andany,
• Jonathan D. Adams and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2019, 10, 2357–2363, doi:10.3762/bjnano.10.226

• , M. Kandpal et al. [42] have shown that embedding ZnO nanoparticles into a pure SU8 matrix increases its Young’s modulus from 8 to 30 GPa. The stiffer cantilever chip body will probably yield better mechanical tuning properties and hence an improved ease of use. Conclusion In this article, a batch

Review of advanced sensor devices employing nanoarchitectonics concepts

• Katsuhiko Ariga,
• Tatsuyuki Makita,
• Masato Ito,
• Taizo Mori,
• Shun Watanabe and
• Jun Takeya

Beilstein J. Nanotechnol. 2019, 10, 2014–2030, doi:10.3762/bjnano.10.198

• processes, such as catalytic reactions and fluorescence quenching, often improves sensor capabilities through component nanoarchitectonics. Imanaka and co-workers used a combustion process induced by a precious-metal-free CeO2–ZrO2–ZnO catalyst for CO gas detection [87]. The semiconducting (p-type) La2CuO4

• -loaded CeO2–ZrO2–ZnO catalyst has a small heat capacity and dramatically increases the temperature of the Pt coil, resulting in a highly sensitive sensor signal. On the other hand, the n-type Sm2CuO4-loaded CeO2–ZrO2–ZnO catalyst is advantageous when rapid response and low temperature operation are

• photoluminescence. The sensing films consisting of paper and ZnO could realize a very sensitive water detection with a relative humidity of less than 1% and the detection of trace-level water of less than 0.05%. In addition, the interference from any small molecules other than water is also avoided. The precise

Prestress-loading effect on the current–voltage characteristics of a piezoelectric p–n junction together with the corresponding mechanical tuning laws

• Wanli Yang,
• Shuaiqi Fan,
• Yuxing Liang and
• Yuantai Hu

Beilstein J. Nanotechnol. 2019, 10, 1833–1843, doi:10.3762/bjnano.10.178

• present are third-generation semiconductors, for instance, ZnO, GaN, CdS, and AlN, with wide bandgap, high breakdown electric field, high thermal conductivity, and even mechanical tunability [3]. They show numerous application prospects in electric devices and sensors, such as energy harvesters [4][5][6

• ] studied the static extensional behavior of a piezoelectric semiconductor nanofiber. Liang et al. [20] analyzed the fundamental characteristics of a cantilevered ZnO nanowire exposed to a transient end force. Recently, Fan et al. [21] and Zhang et al. [22] revisited the bending behavior of a cantilevered

• ZnO nanowire based on the linear phenomenological theory of piezoelectric semiconductors. In their studies, the electric leakage of a bent ZnO nanowire is connected to the semiconductor properties and concluded that a lower doping concentration is more suitable for a bent ZnO nanowire to harvest

Synthesis of nickel/gallium nanoalloys using a dual-source approach in 1-alkyl-3-methylimidazole ionic liquids

• Ilka Simon,
• Julius Hornung,
• Juri Barthel,
• Jörg Thomas,
• Maik Finze,
• Roland A. Fischer and
• Christoph Janiak

Beilstein J. Nanotechnol. 2019, 10, 1754–1767, doi:10.3762/bjnano.10.171

• methanol were found for Ni5Ga3 and NiGa [37]. At 165 °C Ni5Ga3 (δ) yielded 100% selectivity towards methanol [38]. Above 220 °C Ni5Ga3 is even more active than a conventional Cu/ZnO/Al2O3 catalyst with less CO formation in the reverse water-gas shift reaction (rWGS). In Ni5Ga3 the Ga-rich step sites

High-temperature resistive gas sensors based on ZnO/SiC nanocomposites

• Vadim B. Platonov,
• Marina N. Rumyantseva,
• Alexander S. Frolov,
• Alexey D. Yapryntsev and
• Alexander M. Gaskov

Beilstein J. Nanotechnol. 2019, 10, 1537–1547, doi:10.3762/bjnano.10.151

• dispersed silicon carbide (SiC). In this work, ZnO and SiC nanofibers were synthesized by electrospinning of polymer solutions followed by heat treatment, which is necessary for polymer removal and crystallization of semiconductor materials. ZnO/SiC nanocomposites (15–45 mol % SiC) were obtained by mixing

• °C. The ZnO/SiC nanocomposites were characterized by a higher concentration of chemisorbed oxygen, higher activation energy of conductivity, and higher sensor response towards CO and NH3 as compared with ZnO nanofibers. The obtained experimental results were interpreted in terms of the formation of

• an n–n heterojunction at the ZnO/SiC interface. Keywords: electrospinning; high temperature gas sensor; n–n heterojunction; ZnO/SiC nanocomposite; Introduction The risk of air pollution is growing due to the development of new technologies in the chemical, metallurgical and food industries, the use

Gas sensing properties of individual SnO₂ nanowires and SnO₂ sol–gel nanocomposites

• Alexey V. Shaposhnik,
• Dmitry A. Shaposhnik,
• Sergey Yu. Turishchev,
• Olga A. Chuvenkova,
• Stanislav V. Ryabtsev,
• Alexey A. Vasiliev,
• Xavier Vilanova,
• Francisco Hernandez-Ramirez and
• Joan R. Morante

Beilstein J. Nanotechnol. 2019, 10, 1380–1390, doi:10.3762/bjnano.10.136

• nanowire synthesis was developed and reported in detail in the classic work of R. Wagner and W. Ellis [1]. Recently, with the use of this method, SnO2, In2O3, WO3, ZnO and other metal oxide nanowires were obtained [1][2][3][4][5]. Liquid phase synthesis methods have also been widely implemented [6][7][8][9

A highly efficient porous rod-like Ce-doped ZnO photocatalyst for the degradation of dye contaminants in water

• Binjing Hu,
• Qiang Sun,
• Chengyi Zuo,
• Yunxin Pei,
• Siwei Yang,
• Hui Zheng and
• Fangming Liu

Beilstein J. Nanotechnol. 2019, 10, 1157–1165, doi:10.3762/bjnano.10.115

• , Parkville, Victoria 3010, Australia ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), School of Science, RMIT University, Melbourne, VIC 3001, Australia 10.3762/bjnano.10.115 Abstract A mild and simple method was developed to synthesize a highly efficient photocatalyst comprised of Ce-doped ZnO

• rods and optimal synthesis conditions were determined by testing samples with different Ce/ZnO molar ratios calcined at 500 °C for 3 hours via a one-step pyrolysis method. The photocatalytic activity was assessed by the degradation of a common dye pollutant found in wastewater, rhodamine B (RhB), using

• a sunlight simulator. The results showed that ZnO doped with 3% Ce exhibits the highest RhB degradation rate. To understand the crystal structure, elemental state, surface morphology and chemical composition, the photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron

Photoactive nanoarchitectures based on clays incorporating TiO₂ and ZnO nanoparticles

• Eduardo Ruiz-Hitzky,
• Pilar Aranda,
• Marwa Akkari,
• Nithima Khaorapapong and
• Makoto Ogawa

Beilstein J. Nanotechnol. 2019, 10, 1140–1156, doi:10.3762/bjnano.10.114

• ; nanoarchitectures; photocatalysts; titanium dioxide; zinc dioxide; Review Introduction: immobilization of nanoscale TiO2 and ZnO on clay minerals Nanoarchitectonics is a term coined by Japan's National Institute for Materials Science (NIMS), which refers to the nanoscale design of complex materials through a deep

• silicates showing diverse structural arrangements and morphologies (Figure 1) with topologies able to accommodate a variety of NPs of semiconductors such as TiO2 and ZnO. TiO2 and, to a minor extent, ZnO NPs in the form of anatase and wurtzite phases (Figure 1E and 1F, respectively), are semiconducting

• are more efficient as photocatalysts than the corresponding bulk TiO2 and ZnO powders when they are present as NPs. This fact could be simply explained by the fact that the smaller particles normally have a larger surface-to-volume ratio. Many studies have focused on the photocatalytic activities of

CuInSe₂ quantum dots grown by molecular beam epitaxy on amorphous SiO₂ surfaces

• Henrique Limborço,
• Pedro M.P. Salomé,
• Rodrigo Ribeiro-Andrade,
• Jennifer P. Teixeira,
• Nicoleta Nicoara,
• Kamal Abderrafi,
• Joaquim P. Leitão,
• Juan C. Gonzalez and
• Sascha Sadewasser

Beilstein J. Nanotechnol. 2019, 10, 1103–1111, doi:10.3762/bjnano.10.110

• layer, and a CdS/i-ZnO/ZnO:Al front contact. The maximum power conversion efficiency achieved by this type of solar cells has recently achieved a world record of 23.35%, which outperforms all other multi-crystalline solar cells, including multi-crystalline silicon with 22.3% [1][2]. The CIGS layer in

Tailoring the stability/aggregation of one-dimensional TiO₂(B)/titanate nanowires using surfactants

• Atiđa Selmani,
• Johannes Lützenkirchen,
• Kristina Kučanda,
• Dario Dabić,
• Engelbert Redel,
• Ida Delač Marion,
• Damir Kralj,
• Darija Domazet Jurašin and
• Maja Dutour Sikirić

Beilstein J. Nanotechnol. 2019, 10, 1024–1037, doi:10.3762/bjnano.10.103

• different solution and interfacial behavior compared to corresponding conventional monomeric surfactants [32][33][34]. The interaction of gemini surfactants with solid (nano)surfaces such as clay [35], calcium phosphate [36], silica [37][38][39][40], TiO2 [41], ZnO [42] and carbon NTs [43] have been

Electronic and magnetic properties of doped black phosphorene with concentration dependence

• Ke Wang,
• Hai Wang,
• Min Zhang,
• Yan Liu and
• Wei Zhao

Beilstein J. Nanotechnol. 2019, 10, 993–1001, doi:10.3762/bjnano.10.100

• experimentally demonstrated that substitutional doping of TMDs could be achieved by filling the vacancies observed in CVD-grown monolayer TMDs [18]. Liu et al. [19] prepared epitaxial copper-doped ZnO films and observed that the substitution of Cu for Zn and the presence of strong Cu–Zn–O bonds are necessary for

• the ferromagnetism of the ZnO films. Likewise, substitutional doping can also be used for manipulating the electronic and magnetic properties of phosphorene [20][21][22][23]. Zheng et al. [24] focused on the properties of phosphorene doped with non-metal atoms in a 6 × 6 × 1 supercell, corresponding

Direct growth of few-layer graphene on AlN-based resonators for high-sensitivity gravimetric biosensors

• Jimena Olivares,
• Teona Mirea,
• Lorena Gordillo-Dagallier,
• Bruno Marco,
• José Miguel Escolano,
• Marta Clement and
• Enrique Iborra

Beilstein J. Nanotechnol. 2019, 10, 975–984, doi:10.3762/bjnano.10.98

• properly functionalized [1][2], the small sample volumes they require for operation when combined with microfluidics [3], their high-speed response and label-free operation [4]. Piezoelectric resonators based on thin films of, e.g., AlN or ZnO offer significantly greater sensitivities than conventional

Towards rare-earth-free white light-emitting diode devices based on the combination of dicyanomethylene and pyranine as organic dyes supported on zinc single-layered hydroxide

• Jeff L. Nyalosaso,
• Rachod Boonsin,
• Pierre Vialat,
• Damien Boyer,
• Geneviève Chadeyron,
• Rachid Mahiou and
• Fabrice Leroux

Beilstein J. Nanotechnol. 2019, 10, 760–770, doi:10.3762/bjnano.10.75

• variations in the molecular area of each metal atom. TG-DTA measurements (Figure 3c) carried out on the dried Zn-SLH showed mass losses of 39% upon heating to 800 °C through the decomposition of zinc hydroxyacetate up to the fully inorganic ZnO. The associated thermal events are well documented [19] and

• correspond to the loss of two water molecules below 100 °C and four additional molecules below 250 °C, together with acetone and CO2 as well as acetic anhydride to finally form ZnO. The TG-DTA data were used to verify the chemical formula of the compound Zn5(OH)8(CH3COO)2·nH2O. The mass formula at room

• temperature is related to M(RT) = 5·ZnO/(1 − 0.39) leading to 667.29 g·mol−1 (per 5·Zn) and corresponding to a hydration rate of n = 4.79, much higher than the value of 2 that is usually reported. It may be explained by a sample largely hydrated with weakly bonded water molecules as can be inferred from the

On the transformation of “zincone”-like into porous ZnO thin films from sub-saturated plasma enhanced atomic layer deposition

• Alberto Perrotta,
• Julian Pilz,
• Stefan Pachmajer,
• Antonella Milella and
• Anna Maria Coclite

Beilstein J. Nanotechnol. 2019, 10, 746–759, doi:10.3762/bjnano.10.74

• /bjnano.10.74 Abstract The synthesis of nanoporous ZnO thin films is achieved through annealing of zinc-alkoxide (“zincone”-like) layers obtained by plasma-enhanced atomic layer deposition (PE-ALD). The zincone-like layers are deposited through sub-saturated PE-ALD adopting diethylzinc and O2 plasma with

• doses below self-limiting values. Nanoporous ZnO thin films were subsequently obtained by calcination of the zincone-like layers between 100–600 °C. Spectroscopic ellipsometry (SE) and X-ray diffraction (XRD) were adopted in situ during calcination to investigate the removal of carbon impurities

• , development of controlled porosity, and formation and growth of ZnO crystallites. The layers developed controlled nanoporosity in the range of 1–5%, with pore sizes between 0.27 and 2.00 nm as measured with ellipsometric porosimetry (EP), as a function of the plasma dose and post-annealing temperature

A porous 3D-RGO@MWCNT hybrid material as Li–S battery cathode

• Yongguang Zhang,
• Jun Ren,
• Yan Zhao,
• Taizhe Tan,
• Fuxing Yin and
• Yichao Wang

Beilstein J. Nanotechnol. 2019, 10, 514–521, doi:10.3762/bjnano.10.52

• sulfur loading is essential for the practical implementation of Li–S batteries [5][6][7]. To overcome the above-mentioned challenges in Li–S batteries, many strategies have been proposed [8][9][10][11][12]. For example, metal oxides, such as TiO2, ZnO, MnO2, and SiO2, were reported to provide active

Reduced graphene oxide supported C₃N₄ nanoflakes and quantum dots as metal-free catalysts for visible light assisted CO₂ reduction

• Md Rakibuddin and
• Haekyoung Kim

Beilstein J. Nanotechnol. 2019, 10, 448–458, doi:10.3762/bjnano.10.44

• , and CH3OH is one of the sustainable ways to address the issues of both global warming and the energy crisis [1][2][3][4][5][6]. So far, a variety of semiconductor photocatalysts, such as ZnO, TiO2, WO3, and CdS have been developed for the photoreduction of CO2 [7][8][9][10]. However, poor separation

Site-specific growth of oriented ZnO nanocrystal arrays

• Rekha Bai,
• Dinesh K. Pandya,
• Sujeet Chaudhary,
• Veer Dhaka,
• Vladislav Khayrudinov,
• Jori Lemettinen,
• Christoffer Kauppinen and
• Harri Lipsanen

Beilstein J. Nanotechnol. 2019, 10, 274–280, doi:10.3762/bjnano.10.26

• University, Tietotie 3, 02150 Espoo, Finland 10.3762/bjnano.10.26 Abstract We report on the growth of ZnO nanocrystals having a hexagonal, prismatic shape, sized 700 nm × 600 nm, on bare indium tin oxide (ITO) substrates. The growth is induced by a low ion flux and involves a low-temperature

• electrodeposition technique. Further, vertically aligned periodic nanocrystal (NC) growth is engineered at predefined positions on polymer-coated ITO substrates patterned with ordered pores. The vertical alignment of ZnO NCs along the c-axis is achieved via ion-by-ion nucleation-controlled growth for patterned

• nanoscale optoelectronics [1][2][3][4]. ZnO is an important direct band gap (≈3.3 eV), nontoxic, metal oxide semiconductor, which can readily be used for optoelectronic applications. The properties of ZnO can be tailored by changing the morphology of the structures. Thus, fabrication of ZnO having different

Uniform Sb₂S₃ optical coatings by chemical spray method

• Jako S. Eensalu,
• Atanas Katerski,
• Erki Kärber,
• Ilona Oja Acik,
• Arvo Mere and
• Malle Krunks

Beilstein J. Nanotechnol. 2019, 10, 198–210, doi:10.3762/bjnano.10.18

• two-step process on ZnO nanorod/TiO2 substrates [7]. In this study, we applied this two-step process, i.e., depositing amorphous Sb2S3 layers on planar substrates, followed by post-deposition crystallization. The aim of this study was to produce crystalline, continuous, Sb2S3 optical coatings with

New micro/mesoporous nanocomposite material from low-cost sources for the efficient removal of aromatic and pathogenic pollutants from water

• Emmanuel I. Unuabonah,
• Robert Nöske,
• Jens Weber,
• Christina Günter and
• Andreas Taubert

Beilstein J. Nanotechnol. 2019, 10, 119–131, doi:10.3762/bjnano.10.11

• of 31.25, 36.82°, 55.62°, 59.32° and 65.19°), which can be assigned to a new Al2ZnO4-phase (ghn, gahnite-type JCPDF 98-007-5098). Interestingly, the new materials prepared in this study exhibit no ZnO phase, as seen from the FTIR or XRD spectra, unlike in our previous studies [21]. This behavior is

• because a standard solution of NaOH used in the previous preparation of the materials (which, when reacted with ZnCl2, will yield ZnO) was omitted in the preparation of the nanocomposites in this study. Nuclear magnetic resonance spectroscopy analysis To further evaluate the composition and structure of

Zn/F-doped tin oxide nanoparticles synthesized by laser pyrolysis: structural and optical properties

• Florian Dumitrache,
• Iuliana P. Morjan,
• Elena Dutu,
• Ion Morjan,
• Claudiu Teodor Fleaca,
• Monica Scarisoreanu,
• Alina Ilie,
• Marius Dumitru,
• Cristian Mihailescu,
• Adriana Smarandache and
• Gabriel Prodan

Beilstein J. Nanotechnol. 2019, 10, 9–21, doi:10.3762/bjnano.10.2

• atom %) made by spray pyrolysis showing high transparency and bandgap values between 3.86 and 4.45 eV have also been reported [32]. Other researchers have used radio frequency magnetron sputtering of mixed 30 wt % ZnO and 70 wt % SnO2 targets to obtain similar FZTO films, yet their reported different

• samples. For instance, regardless of the Zn doping degree, the presence of the main ZnO peak (101) at 2θ ≈ 36.5° was not distinguished. This result highlighted that at this Zn doping level there is no segregation process toward some Zn-rich crystalline phases such as Zn2SnO4. It is worth to noting that

• precursors to oxides (SnO2 and ZnO, in fact Zn-doped SnO2), CO2 and H2O in the laser pyrolysis reaction zone. Due to the much higher reactivity of metals, the metal oxides are formed with priority, and the unoxidized alkyl radicals from the precursors will undergo a complex process involving reactions such

Femtosecond laser-assisted fabrication of chalcopyrite micro-concentrator photovoltaics

• Franziska Ringleb,
• Stefan Andree,
• Berit Heidmann,
• Jörn Bonse,
• Katharina Eylers,
• Owen Ernst,
• Torsten Boeck,
• Martina Schmid and
• Jörg Krüger

Beilstein J. Nanotechnol. 2018, 9, 3025–3038, doi:10.3762/bjnano.9.281

• state of the art. The electric back contact (molybdenum) covered with the highly-efficient light-absorber (CIGSe) on top is deposited on a carrier material (glass). A buffer layer (CdS), a window layer consisting of an intrinsic ZnO layer (ZnO) and an aluminum-doped ZnO layer (Al:ZnO) as transparent

• . A process to realize such a system is illustrated in Figure 12. Before buffer layers (CdS, ZnO) and front contact (Al:ZnO) can be deposited, the electric insulation between back and front contact in-between the microabsorbers must be ensured. Due to its high (thermal) stability, ease of use and low

• etching (22 min at 250 W in Ar atmosphere), for example, is sufficient to uncover the islands while keeping the molybdenum substrate isolated (Figure 12c). Finally, the buffer layers (CdS, ZnO) and the front contact (Al:ZnO) were deposited (Figure 12d). CdS was applied by a wet-chemical bath deposition