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Highlights Benzamidine derivatives are utilized to differentiate between 2D passivation and amorphous passivation. Introducing an n-type 2D passivation layer enhances the charge extraction and transportation and reduces the interface recombination in inverted perovskite solar cells. The intramolecular charge of organic ligands is critical for the formation of crystalline 2D capping layers on 3D perovskite layers. The long-term stability of inverted perovskite solar cells is improved owing to hydrophobic sealing of 3D perovskite via crystalline 2D capping. The introduction of two-dimensional (2D) perovskite layers on top of three-dimensional (3D) perovskite films enhances the performance and stability of perovskite solar cells (PSCs). However, the electronic effect of the spacer cation and the quality of the 2D capping layer are critical factors in achieving the required results. In this study, we compared two fluorinated salts: 4-(trifluoromethyl) benzamidine hydrochloride (4TF-BA·HCl) and 4-fluorobenzamidine hydrochloride (4F-BA·HCl) to engineer the 3D/2D perovskite films. Surprisingly, 4F-BA formed a high-performance 3D/2D heterojunction, while 4TF-BA produced an amorphous layer on the perovskite films. Our findings indicate that the balanced intramolecular charge polarization, which leads to effective hydrogen bonding, is more favorable in 4F-BA than in 4TF-BA, promoting the formation of a crystalline 2D perovskite. Nevertheless, 4TF-BA managed to improve efficiency to 24%, surpassing the control device, primarily due to the natural passivation capabilities of benzamidine. Interestingly, the devices based on 4F-BA demonstrated an efficiency exceeding 25% with greater longevity under various storage conditions compared to 4TF-BA-based and the control devices.

We report the amorphous Si passivation of Ge pMOSFETs fabricated on (001)-, (011)-, and (111)-orientated surfaces for advanced CMOS and thin film transistor applications. Amorphous Si passivation of Ge is carried out by magnetron sputtering at room temperature. With the fixed thickness of Si t Si , (001)-oriented Ge pMOSFETs achieve the higher on-state current I ON and effective hole mobility μ eff compared to the devices on other orientations. At an inversion charge density Q inv of 3.5 × 10 12  cm −2 , Ge(001) transistors with 0.9 nm t Si demonstrate a peak μ eff of 278 cm 2 /V × s, which is 2.97 times higher than the Si universal mobility. With the decreasing of t Si , I ON of Ge transistors increases due to the reduction of capacitive effective thickness, but subthreshold swing and leakage floor characteristics are degraded attributed to the increasing of midgap D it .

Amorphous silicon carbide (a-SiC) is a wide-bandgap semiconductor with high robustness and biocompatibility, making it a promising material for applications in biomedical device passivation. a-SiC thin film deposition has been a subject of research for several decades with a variety of approaches investigated to achieve optimal properties for multiple applications, with an emphasis on properties relevant to biomedical devices in the past decade. This review summarizes the results of many optimization studies, identifying strategies that have been used to achieve desirable film properties and discussing the proposed physical interpretations. In addition, divergent results from studies are contrasted, with attempts to reconcile the results, while areas of uncertainty are highlighted.

The microstructure factor ( R* ) of the PECVD-grown intrinsic amorphous silicon (i-a-Si:H) layer plays a crucial role in crystalline silicon (c-Si) surface passivation and charge carrier transport in silicon heterojunction (SHJ) solar cells. In this work, we have used stack of i-a-Si:H passivation layers deposited at two different temperatures to improve the c-Si surface passivation by minimizing the interface defect density at the a-Si/c-Si interface. The initial i 1 -a-Si:H layer is deposited on the c-Si at ~ 150 °C with a high R* , and the second i 2 -a-Si:H layer is deposited at 230 °C with a low R* . Ex-situ ellipsometry analysis of i-a-Si:H layers provided information related to the void fraction of the thin films due to modification in the Si–H ≥2 and Si–H bonding environment, which plays a vital role in atomic H migration towards i-a-Si:H/c-Si interface. Combining the low- and high-temperature i-a-Si:H layer stack enhanced the cell precursor passivation to ~ 2.1 ms with an implied V oc of ~ 714 mV. Furthermore, implementing the optimized thickness (2 nm + 8 nm) of the i-a-Si:H stack (with 40% void fraction in i 1 -a-Si:H layer) in the device has led to the power conversion efficiency of ~ 19.06%.

The effect of the Cr element on the corrosion behavior of as-spun Fe72−xCrxB19.2Si4.8Nb4 ribbons with x = 0, 7.2, 21.6, and 36 in 3.5% NaCl solution were investigated in this work. The results show that the glass formability of the alloys can be increased as Cr content (cCr) is added up to 21.6 at.%. When cCr reaches 36 at.%, some nanocrystals appear in the as-spun ribbon. With increasing cCr content, the corrosion resistances of as-spun Fe-based ribbons are continually improved as well as their hardness properties; during the polarization test, their passive film shows an increase first and then a decrease, with the highest pitting potential as cCr = 7.2 at.%, which is confirmed by an XPS test. The dense passivation film, composed of Cr2O3 and [CrOx(OH)3−2x, nH2O], can reduce the number of corrosion pits on the sample surface due to chloride corrosion and possibly be deteriorated by the overdosed CrFeB phase. This work can help us to design and prepare the highly corrosion-resistant Fe-based alloys.

To meet the surging needs in energy efficiency and eco-friendly lubricants, a novel superlubricious technology using a vegetable oil and ceramic materials is proposed. By coupling different hydrogen-free amorphous carbon coatings with varying fraction of sp 2 and sp 3 hybridized carbon in presence of a commercially available silicon nitride bulk ceramic, castor oil provides superlubricity although the liquid vegetable oil film in the contact is only a few nanometres thick at most. Besides a partial liquid film possibly separating surfaces in contact, local tribochemical reactions between asperities are essential to maintain superlubricity at low speeds. High local pressure activates chemical degradation of castor oil generating graphitic/graphenic-like species on top of asperities, thus helping both the chemical polishing of surface and its chemical passivation by H and OH species. Particularly, the formation of the formation of −(CH 2 −CH 2 ) n − noligomers have been evidenced to have a major role in the friction reduction. Computer simulation unveils that formation of chemical degradation products of castor oil on friction surfaces are favoured by the quantity of sp 2 -hybridized carbon atoms in the amorphous carbon structure. Hence, tuning sp 2 -carbon content in hydrogen-free amorphous carbon, in particular, on the top layers of the coating, provides an alternative way to control superlubricity achieved with castor oil and other selected green lubricants.

Visible‐light photodetectors (VPDs) garner significant attention due to their diverse applications in optical communication. However, conventional VPDs struggle to achieve both transparency and flexibility, limiting their use in emerging technologies. Hydrogenated amorphous silicon (a‐Si:H) offers a promising platform for flexible optoelectronics for compatibility with substrates, although temperature reduction causes degradation of electrical and optical properties due to insufficient hydrogen passivation. In this study, the effect of the hydrogen‐to‐silane (H2/SiH4; f ratio) gas is systematically investigated ratio on the microstructural, optical, and electrical properties of a‐Si:H films synthesized at an ultra‐low temperature of 90 °C using plasma‐enhanced chemical vapor deposition (PECVD). Raman and Fourier‐transform infrared (FT‐IR) spectroscopy reveal that an optimized H2/SiH4 ratio minimizes Si─H2 bonding, effectively reducing defect density and improving film stability. Spectroscopic ellipsometry confirms that this ratio optimizes the refractive index and optical bandgap, enhancing light absorption. Electrical measurements demonstrate that photodiodes with the optimized a‐Si:H layer exhibit superior photosensitivity and suppressed dark current (f2: 20.6 and f8: 2.70 × 10−10 A, respectively), attributed to improved carrier transport and reduced Shockley–Read–Hall (SRH) recombination. Furthermore, flexible photodetectors maintain high mechanical reliability under repeated bending cycles. These findings highlight the potential of ultra‐low‐temperature PECVD a‐Si:H films for high‐performance, flexible photodetectors. Hydregen content was tailored during ultra‐low‐temperature plasma‐enhanced chemical vaper deposition (PECVD) to deposit hydrogenated amorphous silicon (a ‐ Si:H) films, and the effect of the hydrogen dilution ratio on defect suppression was analyzed. The optimized condition yielded a photodetector with a high responsivitiy of 338 mA/W and excellent mechanical stability, enabling a flexible visible‐light photodetector (VPD).

The crystallization of hydrogenated amorphous silicon (a-Si:H) is essential for improving solar cell efficiency. In this study, we analyzed the crystallization of a-Si:H via excimer laser annealing (ELA) and compared this process with conventional thermal annealing. ELA prevents thermal damage to the substrate while maintaining the melting point temperature. Here, we used xenon monochloride (XeCl), krypton fluoride (KrF), and deep ultra-violet (UV) lasers with wavelengths of 308, 248, and 266 nm, respectively. Laser energy densities and shot counts were varied during ELA for a-Si:H films between 20 and 80 nm thick. All the samples were subjected to forming gas annealing to eliminate the dangling bonds in the film. The ELA samples were compared with samples subjected to thermal annealing performed at 850–950 °C for a-Si:H films of the same thickness. The crystallinity obtained via deep UV laser annealing was similar to that obtained using conventional thermal annealing. The optimal passivation property was achieved when crystallizing a 20 nm thick a-Si:H layer using the XeCl excimer laser at an energy density of 430 mJ/cm2. Thus, deep UV laser annealing exhibits potential for the crystallization of a-Si:H films for TOPCon cell fabrication, as compared to conventional thermal annealing.

The NO anneal has been shown to effectively remove 99% of defects in SiC based devices. However, the details of interactions of NO molecules with amorphous (a)-SiO2 and SiC/SiO2 interface are still poorly understood. We use DFT simulations to investigate the NO incorporation energies in a-SiO2, and how these are affected by the steric environment. The results explain the ease with which NO molecules incorporate into a-SiO2 and give an insight into the diffusion paths they take during annealing. We highlight the importance of exhaustive sampling for exploring NO diffusion pathways.

Impurities are of crucial interest in optoelectronic devices as they affect carrier lifetimes and electrical properties. In view of that, it is important to incorporate certain processing steps to reduce impurities effect on final devices. The aim of this work is to enhance silicon carbide SiC purity for silicon passivation. Low cost method of SiC purification is presented. This method combines three main steps consisting of formation of porous silicon carbide layers by acid vapor etching followed by a photo-thermal annealing at different temperatures. Finally, obtained SiC powder was subject to a chemical treatment to remove porous SiC layer. Effect of gettering temperature on purification efficiency was evaluated by inductively coupled plasma atomic emission spectrometry (ICP-AES). The gettering experiment was performed at 800–950 °C, and optimum results were obtained at 950 °C. SiC purity is improved from 3 N (99.977%) to 5 N (99.999%) with an impurity removal efficiency of 96.56%. Purified SiC was used as a target to synthesize SiC layers using pulsed laser deposition technique (PLD) for optoelectronic devices. The use of intrinsic amorphous silicon carbide (a-SiC) passivating layers was investigated especially by photoconductivity decay technique. Improved SiC target purity leads to a significant enhancement of a-SiC passivating properties attributed to the surface recombination velocity decrease. Electrical properties of a-SiC/c-Si(p) were also studied using I-V and C-V techniques.