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The key mechanisms for the superlubricity of the DLC film in a vacuum environment are considered to be the formation of graphitization at the friction interface and the carbon dangling bonds on the surface of the H-passivated film. However, how the graphitization and H-passivation mechanisms affect the superlubricity of DLC films in a vacuum environment has not been uniformly understood. This paper attempts to explore the influence of the H-passivation and graphitization mechanism on the frictional properties of DLC films by means of first-principles calculations and molecular dynamics simulation and provides an atomic-level view of the super-slip mechanism of DLC films in a vacuum environment. The results show that the separation work of G/C (2.77 J/m2) and C/H–C (0.19 J/m2) is reduced by 80% and 98%, respectively, compared to C/C (13.52 J/m2). However, it is interesting to note that the separation work of the G/H–C interface (0.51 J/m2) is 168% higher than that of the C/H–C interface (0.19 J/m2). The results of the molecular dynamics simulation also show that the C/H–C interface maintains a small and stable frictional force due to the lower interface slip and the lower temperature rise of the interface. Further investigations revealed that the main reason for the higher separation work is the high charge transfer between the G/H–C interface. In short, the H-passivation in a vacuum environment is the key mechanism that determines the superlubricity of DLC films. [ABSTRACT FROM AUTHOR]

We successfully demonstrated a hydrogen (H 2)-passivated HfO 2 -based memristive device that operates with a low current that is below sub-nA in this paper. Gradual resistance changes are achieved with the diversification of the sweeping voltage. The H 2 -passivated HfO 2 -based memristive device shows an improvement of the device's performance of low power consumption with sub-nA, data retention for 104 s, and robust endurance of 106 repetitive cycles. The Spike Timing Dependent Plasticity (STDP) and the pattern recognition via MNIST are employed to assess the artificial neural network characteristics of the proposed device. A symmetrical curve on STDP is observed for an H 2 -passivated HfO 2 -based memristive device, which indicates that it can facilitate in order to mimic a human brain. The high accuracy of 91.12% and a clearer pattern recognition are obtained on an H 2 -passivated memristive device. Therefore, we believe that the H 2 -passivated HfO 2 -based memristive device opens up a new path in order to mimic the human brain with low power. [ABSTRACT FROM AUTHOR]

We report p-GaN passivation via hydrogen plasma used to create current blocking regions (CBRs) in InGaN-based green LEDs with standard dimensions of 280 × 650 μm2. The CBRs are created before mesa etching in two variants: underneath the opaque metal p-pad and both underneath the p-pad and along the device's mesa perimeter. The peak EQE increased by 13% and 23% in the first and the second cases, respectively, in comparison to the reference LED with no CBR. With a high injection current of 50 A/cm2, the EQE value increased by 2% in the case of CBRs underneath the p-pad as well as by 14% in the case of CBRs both underneath the p-pad and along the mesa perimeter (relative to the reference sample with no CBR). [ABSTRACT FROM AUTHOR]

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 sp2 and sp3 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 −(CH2−CH2)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 sp2-hybridized carbon atoms in the amorphous carbon structure. Hence, tuning sp2-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. [ABSTRACT FROM AUTHOR]

Charge-trap based resistive switching (RS) has attracted attention in the resistive random-access memory (RRAM) industry due to its gradual RS behavior for multi-level and synaptic applications. In this work, in order to lower the operating current level closely related to device’s degradation, we applied a hydrogen passivation to Zr3N2 based RRAM devices and investigated the correlation between current level and trap density, such as an interface trap density ( $\text{N}_{\mathrm {it}}$ ) at the Zr $_{3}\text{N}_{2}/p$ -Si layer and nitride trap density ( $\text{N}_{\mathrm {nt}}$ ) within Zr3N2 films, for memory cells annealed in conventional N2 gas as well as H2 gas. Compared to the N2-annealed sample, after H2 annealing, $\text{N}_{\mathrm {it}}$ is lowered by the hydrogen passivation effect, which results in a reduction of both current level at high resistive state (HRS) and variation of HRS and low resistive state (LRS). As a result, in the H2 annealed Zr3N2 RRAM cell, we observed a lower operation voltage/current, longer endurance, and larger read margin due to the hydrogen passivation effect.

We have studied the effects of proton irradiation on the AlGaN/GaN HEMTs with AlN buffer layer as well as conventional GaN buffer layer. It was found that a short time proton irradiation (~ 50 sec) can promote beneficial effects on device performances, which results in great reduction in the off-state leakage current and the gate leakage current without degrading the output current and transconductance. The pulsed I-V measurement demonstrated that both devices exhibit greatly improved current dispersion characteristics and, particularly, the device with AlN buffer layer shows stronger radiation hardness than that of the device with GaN buffer layer. These interesting results are believed to be due to the hydrogen passivation with thermal annealing effect during the proton irradiation. It is expected that the proper irradiation condition such as fluence, energy, and time is crucial to improve the device performances, rather than to deteriorate the performances.

Hydrogen (H) passivation is one of ideal candidates to reduce interfacial and bulk defects for providing good passivation by the light soaking process. Herein, we investigate the influence of the medium-temperature light soaking process on the passivation and electronic performance of the N-TOPCon solar cells. The medium-temperature light soaking process had the significant impact on the metallization-induced recombination of the p++ layer and the Si substrate with a corroded silver (Ag) at a depth of >165 nm. During the light soaking process, the breaking the bending of (Si:H 2) n bonds causes H transitions from a bound state in the Si–H bond to a free state. In this state, H captures movable Ag and boron atoms on the wafer's surface for passivation. The mechanism for enhancing the passivation on the metallization-induced recombination under the metal contact (J 0 , metal) of SiO x /n+-poly-Si layer, the emitter dark saturation current density under the passivation layer (J 0) of p+ layer, and SiO x /n+-poly-Si layer is to prevent the formation of new defects by removing excess H. An efficiency gain of 0.87 % was observed after the light soaking process, attributed to the increase in open circuit voltage (V oc), short circuit current density (J sc), and fill fact (FF) values by 10 mV, 0.15 mA/cm2, and 1.5 %, respectively. The partial gain of FF comes from the effect of medium-temperature enhanced metal contact. This research contributes to a profound understanding of the mechanism behind improving the medium-temperature light soaking process improvement and offers a feasible strategy for enhancing the efficiency N-TOPCon solar cells. After optimizing the front surface recombination and the medium-temperature light soaking processes, we manufactured industrial-grade TOPCon cells with in-house efficiency (E ff), V oc , J sc , and FF values as high as 25.8 %, 729 mV, 42.1 mA/cm2, and 84 %, respectively. • Light Soaking process is one of ideal candidates of Hydrogen passivation. • J 0 , J 0 , metal , S eff , ρ c , the ratio of Si–H content and the I–V parameters were investigated. • Cells with the light soaking processes exhibited the efficiency gain of 0.87 %. • A industrial-grade efficiency >25.8 % of cells treated with optimized light soaking process. [ABSTRACT FROM AUTHOR]

In view of the problem that the photoelectric conversion efficiency of P-type passivated emitter rear contact (PERC) solar cells reduces due to the influence of potential induced degradation and damp-heat degradation during the service period, the degraded solar cells were recovered by photo & electric injection and thermal annealing process. In the meantime, the efficiency improvement mechanism was studied. The experimental results show that 94. 32% of degraded solar cells are recovered successfully, and the average photoelectric conversion efficiency of all investigated cells is increased by 8.96%, under the optimal experimental conditions of 3 times standard sunlight intensity, 10 A of electric injection current, 150 t of annealing temperature, and 50 min of processing. The results of photoluminescence spectra and quantum efficiency show that the photoelectric injection and thermal annealing can effectively reduce the internal and rear surface defects of silicon substrate caused by potential induced degradation and damp-heat degradation, and the photoelectric conversion efficiency of degraded solar cells can be finally improved. [ABSTRACT FROM AUTHOR]

Porous silicon films formed by metal-assisted chemical etching using H2O2 and KMnO4 oxidants are studied by Raman spectrometry and infrared absorption spectrometry. It is found that etching using H2O2 makes it possible to obtain por-Si films with stronger carrier depletion and lower mechanical stresses than those using KMnO4. The effect of hydrogen passivation in por-Si films of samples under study is not observed. It is shown that the carrier depletion in the por-Si film is caused by partial etching of impurity atoms during metal-assisted etching. [ABSTRACT FROM AUTHOR]

We report p-GaN passivation via hydrogen plasma used to create current blocking regions (CBRs) in InGaN-based green LEDs with standard dimensions of 280 × 650 μm2. The CBRs are created before mesa etching in two variants: underneath the opaque metal p-pad and both underneath the p-pad and along the device’s mesa perimeter. The peak EQE increased by 13% and 23% in the first and the second cases, respectively, in comparison to the reference LED with no CBR. With a high injection current of 50 A/cm2, the EQE value increased by 2% in the case of CBRs underneath the p-pad as well as by 14% in the case of CBRs both underneath the p-pad and along the mesa perimeter (relative to the reference sample with no CBR).

For the passivated emitter and rear cells with bifacial power generation (known as PERC+), the rear-side efficiency is very important and critical. In this work, the influence of SiN x and SiO x N y as rear-side passivation films on the performance of PERC + cells was investigated. It was found that the SiN x film is better in terms of passivation performance and resistance to aluminum paste erosion, while the SiO x N y film exhibits a better optical performance. To synthesize the benefits of SiN x and SiO x N y , the multi-layer SiN x /SiO x N y /SiN x stacks were designed with the Wafer ray tracer system. The front-side efficiency of the optimized cells with SiN x /SiO x N y /SiN x passivation stacks was increased by 0.09 % as compared with the cells passivated with a single SiN x film of 80 nm in thickness. Moreover, in contrast with the cells with a rear-side SiN x film of 150 nm in thickness and the basically same front-side efficiency, the rear-side efficiency and bifaciality were increased by 1.55 % and 6.79 %, respectively. • SiO x N y film can not provide good interface and bulk passivation. • SiO x N y film is weakly resistant to erosion by aluminum paste. • SiO x N y film leads to high optically generated current density under simulation. • Cell with SiN x /SiO x N y /SiN x stack shows high conversion efficiency and bifaciality. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is a technologically significant material. A recent report on the abundance of C60 fullerenes in interstellar space, along with the presence of SiC precursors, sparked interest in potentially similar SiC nanostructures. C60 fullerene was found experimentally and is an exceptionally stable form of carbon. As Si and C have similar valence electron properties, it has been long envisioned that Si and SiC could also form similar fullerene-type structures. In this paper, Si30C30 fullerene-derived clusters were studied from the first principle, starting from an ideal Si60 fullerene template with various arrangements of silicon and carbon atoms and then relaxing them without any symmetry constraint. Hydrogen passivation was considered as well to model the effect of ligands that may be available during chemical synthesis processes. We have found that, after passivation, the relative stability of different configurations of Si30C30 clusters changed compared to the unpassivated structures, while some structures collapsed. We have also noticed several Si–Si and Si–C double bonds in the unpassivated structures. Upon relaxation, some Si atoms lost their hydrogen, while carbon atoms capture those hydrogen atoms. Finally, we tested the endohedral doping of a transition metal, tungsten atom, to stabilize and magnetize Si30C30. With hydrogen passivation, the magnetic moment on W atom was enhanced. Overall, the effects of passivation on these fullerene structures are not very straightforward.

In this work, density functional theory (DFT) was utilized to study the influence of the porosity on the structural, electronic and vibrational properties of porous silicon (PS). It is based on the potential plane wave (PP-PW) method within generalized gradient approximation (GGA). Supercell model was used to simulate nanopores structures. The results obtained from the formation energy calculation exhibited that the most stable structure corresponds to the highest porosity (40.62%). Moreover, a direct band gap is calculated for all porosities and enlargement of energy gap with porosity was observed. The obtained IR spectra calculation show a resemblance between 15.62 and 40.62% porosities and 3.12 and 28.12% porosities. In order to confirm the theoretical results, we prepared porous silicon specimens by electrochemical etching of (001) p-type silicon wafer (1–10 Ohm cm resistivity). In addition, the IR spectra of PS layers were measured and compared against the calculated spectra. IR absorbance spectrum obtained for a porosity of 40.62% shows great agreement with the experimental one and confirms that the surface is hydrogenated. [ABSTRACT FROM AUTHOR]

• In this work, the influence of BEOL process on poly-Si grain boundary traps passivation in 3D NAND flash memory is investigated. • It is found that H rich passivation layer is dominant hydrogen source in poly-Si channel grain boundary traps (GBT) passivation, compared with hydrogen in ambience. • The degree of GBTs passivation can be improved by adjusting hydrogen content stored in dielectrics. • Besides, different interlayer films in BEOL process are found to be critical to cell device characteristics. • It is considered that BEOL film stacks can influence poly-Si GBT density and cell device characteristics during subsequent hydrogen passivation process. In this work, the influence of BEOL process on poly-Si grain boundary traps passivation in 3D NAND flash is investigated. Two hydrogenation methods in final passivation process are compared and hydrogen in passivation layer is found to be more effective for poly-Si grain boundary traps (GBT) passivation, according to device characteristics. Interlayer used as copper cap layer can also act as potential hydrogen diffusion source as well as final passivation layer. Besides, different interlayer films in BEOL process are found to be critical to cell device characteristics. It is considered that BEOL film stacks can influence poly-Si GBT density and cell device characteristics during subsequent hydrogen passivation process. [ABSTRACT FROM AUTHOR]

Abstract Based on the semiconductor transport theory, a computational model for the axial conductivity of one-dimensional nanowires is established. Utilizing the band structure data from the first principles, the conductivity, carrier concentration and mobility of phosphorus doped SiCNWs (P-SiCNWs) before and after passivation were numerically simulated. The results show that hydrogen passivation can greatly improve the conductivity of P-SiCNWs, above room temperature, the conductivity is improved nearly two orders of magnitude, and enhance the thermal stability. The reason is that hydrogen passivation saturates the surface dangling bonds, leading to the disappearance of discrete impurity band of P-SiCNWs. In addition, the surface dangling bonds lead to greater thermal instability of conductivity under room temperature, but this thermal instability decrease rapidly with the increase of temperature. The study will help us to understand the transport properties of low dimensional semiconductors, and provide theoretical support for the research of nano electronic and optoelectronic devices. Highlights • The conductivity formula of a nanowires was established by using 1-D quantum state and Fermi distribution function. • Utilizing the band structure data from the first principles, the transport properties of phosphorus doped SiCNWs were numerically simulated. • Hydrogen saturates the surface dangling bonds, leading to the conductivity is improved nearly two orders of magnitude.. [ABSTRACT FROM AUTHOR]

In a multicrystalline silicon (mc-Si) wafer, trapping effects frequently occur in the carrier lifetime measurement based on the quasi-steady-state photoconductance (QSSPC) technique. This affects the accurate measurement of the carrier lifetime of an mc-Si solar cell by causing distortions at a low injection level close to the Pmax point. Therefore, it is necessary to understand this effect and effectively minimize the trapping-center density. In this study, the variations in the minority carrier-trapping effect of hydrogen at different annealing temperatures in an mc-Si were observed using QSSPC, time-of-flight secondary ion mass spectroscopy, and atom probe tomography. A trapping effect was confirmed and occurred in the grain boundary area, and the effect was reduced by hydrogen. Thus, in an mc-Si wafer, effective hydrogen passivation on the grain area and grain boundary is crucial and was experimentally proven to minimize the distortion of the carrier lifetime.

Oxygen precipitates (OPs) are unavoidably formed in Czochralski silicon (CZ-Si) containing relatively high concentrations of oxygen. The recombination behavior of such defects is also vital for bulk devices like solar cells as they can reduce the minority carrier lifetime and degrade the cell performance. In our experiments, the characteristics of oxygen precipitation in n-type CZ-Si are systematically investigated by means of Fourier transform infrared spectroscopy (FTIR), deep level transient spectroscopy (DLTS) and electron beam induced current (EBIC). It is found that the iron contamination in n-type CZ-Si can strongly influence the OPs generation and their electrical properties, whereas the hydrogen passivation can effectively reduce the recombination activity of OPs. [ABSTRACT FROM AUTHOR]

Dislocation, one of typical crystallographic defects in silicon, is detrimental to the minority carrier lifetime of silicon wafer. Hydrogen passivation is able to reduce the recombination activity of dislocation, however, the passivation efficacy is strongly dependent on the experimental conditions. In this paper, a model based on the theory of hydrogen charge state control is proposed to explain the passivation efficacy of dislocation correlated to the peak temperature of thermal annealing and illumination intensity. Experimental results support the prediction of the model that a mix of positively charged hydrogen and negatively charged hydrogen at certain ratio can maximise the passivation efficacy of dislocation, leading to a better power conversion efficiency of silicon solar cell with dislocation in it. [ABSTRACT FROM AUTHOR]

Aiming at an improved molecular scale understanding of the interaction of water with Ru surfaces and electrodes, in particular with respect to thermally induced water dissociation, we have performed a systematic study of the low temperature adsorption and structure formation behavior of water on Ru(0001) by scanning tunneling microscopy (STM). Typical structures formed upon adsorption at below 100 K indicate the presence of molecularly adsorbed water. For adsorption at 120 K, in contrast, the resulting structures are identical to phases which have been associated with partially dissociated adsorbed water, indicating that for continuous adsorption under these conditions thermally induced water dissociation is activated. This assignment is supported by the strongly hindered activity for further adsorption of H 2 O or CO (at 100 K) on surfaces where only half of the surface is covered by structures related to an adsorbed H 2 O/OH phase. This is attributed to passivation by a H adlayer on the remaining, apparently bare surface areas, which results from H 2 O dissociation. Consequences of these findings on the understanding of water interaction with Ru(0001) are discussed. [ABSTRACT FROM AUTHOR]

First-principles calculations were carried out to predict the stability, electronic, and hydrogen passivation properties of PdS 2 nanoribbons (PdS 2 NRs) with either zigzag- or armchair-terminated edges. Based the energy analysis, we reveal that the armchair NRs are more stable than the zigzag ones. Bare zigzag PdS 2 NRs are metallic, irrespective of the ribbon width. On the other hand, bare armchair NRs change from metal to semiconductor when the ribbon width is greater than 1.24 nm. In addition, different hydrogen passivation type in the armchair direction leads to distinct electronic and magnetic properties of the PdS 2 NRs. [ABSTRACT FROM AUTHOR]

Deuterium (D2) annealing was applied to a poly-crystalline silicon thin-film transistor (poly-Si TFT) to improve reliability and performance. The field-effect electron mobility (μ) was extracted using the gate transconductance (gm) method. It was found that μ was improved before and after D2 annealing. The interface trap density (Dit) as well as the oxide trap density (Not) in the poly-Si TFTs was quantitatively extracted using both conventional dc I--V characterization and analysis of low frequency noise (LFN). The profile of Not along the depth direction was investigated before and after D2 annealing using LFN characteristics. It was confirmed that Dit as well as Not was reduced by the D2 annealing, resulting in a reduction in power spectral density and variation. [ABSTRACT FROM AUTHOR]

The electronic structure and optical properties of the nitrogen and phosphorus doped silicon carbide nanowires (SiCNWs) are investigated using first-principle calculations based on density functional theory. The results show doping can change the type of the band gap and improve the conductivity. However, the doped SiCNWs form a discrete impurity levels at the Fermi energy, and the dispersion degree decreases with the diameter increasing. In order to reveal the root of this phenomenon, we hydrogenated the doped SiCNWs, found that the surface dangling bonds were saturated, and the discrete impurity levels are degeneracy, which indicates that the discrete impurity band of the doped SiCNWs is derived from the dangling bonds. The surface passivation can degenerate the impurity levels. Therefore, both doping and surface passivation can better improve the photoelectric properties of the SiCNWs. The result can provide additional candidates in producing nano-optoelectronic devices. [ABSTRACT FROM AUTHOR]

This paper discusses developments in the mitigation of light-induced degradation caused by boron-oxygen defects in boron-doped Czochralski grown silicon. Particular attention is paid to the fabrication of industrial silicon solar cells with treatments for sensitive materials using illuminated annealing. It highlights the importance and desirability of using hydrogen-containing dielectric layers and a subsequent firing process to inject hydrogen throughout the bulk of the silicon solar cell and subsequent illuminated annealing processes for the formation of the boron-oxygen defects and simultaneously manipulate the charge states of hydrogen to enable defect passivation. For the photovoltaic industry with a current capacity of approximately 100 GW peak, the mitigation of boron-oxygen related light-induced degradation is a necessity to use cost-effective B-doped silicon while benefitting from the high-efficiency potential of new solar cell concepts. [ABSTRACT FROM AUTHOR]

Cast-mono crystalline silicon wafers contain crystallographic defects, which can severely impact the electrical performance of solar cells. This paper demonstrates that applying hydrogenation processes at moderate temperatures to finished screen print cells can passivate dislocation clusters within the cast-mono crystalline silicon wafers far better than the hydrogenation received during standard commercial firing conditions. Efficiency enhancements of up to 2% absolute are demonstrated on wafers with high dislocation densities. The impact of illumination to manipulate the charge state of hydrogen during annealing is investigated and found to not be significant on the wafers used in this study. This finding is contrary to a previous study on similar wafers that concluded increased H or H from laser illumination was responsible for the further passivation of positively charged dangling bonds within the dislocation clusters. [ABSTRACT FROM AUTHOR]

In this work, the SiO 2 -matrix B-doped Si-NC (BDS) thin films have been modified by hydrogen-ion implantation to improve their conductivity. The effects of hydrogen-ion energy on the structural and electrical properties of Si-NC thin films were investigated systematically using photoluminescence, X-ray photoelectron spectroscope and Hall measurements. Results showed that the order of the thin-film surface structure was perfected, the defect density and resistivity were both firstly reduced and then increased when the hydrogen-ion energy was increased from 0 eV to 500 eV. The BDS thin films passivated with hydrogen-ion implantation of 100 eV exhibited the lowest resistivity. The change in micro-structure and resistivity of the BDS thin films probably resulted from hydrogen ions which facilitated diffusion of the surface atoms and H atoms which passivated the defects. [ABSTRACT FROM AUTHOR]

This paper discusses developments in the mitigation of light-induced degradation caused by boron-oxygen defects in boron-doped Czochralski grown silicon. Particular attention is paid to the fabrication of industrial silicon solar cells with treatments for sensitive materials using illuminated annealing. It highlights the importance and desirability of using hydrogen-containing dielectric layers and a subsequent firing process to inject hydrogen throughout the bulk of the silicon solar cell and subsequent illuminated annealing processes for the formation of the boron-oxygen defects and simultaneously manipulate the charge states of hydrogen to enable defect passivation. For the photovoltaic industry with a current capacity of approximately 100 GW peak, the mitigation of boron-oxygen related light-induced degradation is a necessity to use cost-effective B-doped silicon while benefitting from the high-efficiency potential of new solar cell concepts.

Synthesized borophene nanoribbons are the single-atom-thick self-assembly of light weight boron atoms separated by hexagonal hole arrays. In this current study, van der Waals corrected density functional theory have been employed to inspect the interaction of Na with both edge hydrogen passivated β 12 -borophene nanoribbon, based upon first-principles calculations. It is found that the six member ring site is favorable location for Na insertion. Gradual decrease in adsorption energies is observed with increasing Na concentration owing to the fact that the number of vacant sites on anchoring nanoribbon decreases and metal–metal electrostatic repulsion increases. The chemical stoichiometry of full sodiated nanoribbon corresponds to B 11 H 2 Na 7 with a maximum gravimetric capacity of 1551.65 mAhg−1 without the sacrifice of Na mobility (diffusion barrier of 0.38 eV). Bader charge investigation reveals that 0.83 | e | is transferred from Na atom, implying high electronic conductivity of B 33 H 6 nanoribbon during the adsorption process. The average insertion potential is obtained as 0.66 V versus Na/Na + , lying into 0.1–1 V desirable anode potential range. Our study confirm that β 12 -borophene nanoribbon holds a great potential to act as a propitious negative electrode material for sodium-ion rechargeable batteries based on its structural, electronic and electrochemical properties. [Display omitted] • Borophene nanoribbon is investigated by DFT as anode in Na ion batteries. • Structural, mechanical and thermodynamic stability of the 1d layer has been investigated. • Storage capacity of 1551.65 mAhg-1 assisted with low diffusion barrier of 0.38 eV is obtained. • Average voltage of 0.66 V renders borophene nanoribbon as reversible storage material. [ABSTRACT FROM AUTHOR]

Here we report on modeling kinetics of the boron-oxygen defect system in crystalline silicon solar cells. The model, as supported by experimental data, highlights the importance of defect formation for mitigating carrier-induced degradation. The inability to rapidly and effectively passivate boron-oxygen defects is primarily due to the unavailability of the defects for passivation, rather than any “weakness” of the passivation reaction. The theoretical long-term stability of modules in the field is investigated as a worst-case scenario using typical meteorological year data and the System Advisor Model (SAM). With effective mounting of the modules, the modelling indicates that even in desert locations, destabilisation of the passivation is no concern within 40 years. We also incorporate the quadratic dependence of the defect formation rate on the total hole concentration, and highlight the influence of changing doping densities or changing illumination intensity on the CID mitigation process. [ABSTRACT FROM AUTHOR]

In this article, the impact of hydrogenation on the electrical properties of impurity (Fe)-contaminated silicon grain boundaries (GBs) is investigated using capacitance-voltage (C-V) and capacitance transient (C-t) techniques with hybrid orientation direct-silicon-bonded (DSB) wafers. The samples consist of a 2.3 μm thick (110) Si layer on a p-type (100) Si substrate produced via hydrophilic wafer bonding, cleavage, and epithickening. It was found that for a relatively clean GB, the density of the GB states ( D) is ∼6 × 10 eVcm, and the charge neutral level is ∼0.53 eV from the valance band. D increases to more than 2 × 10 eVcmafter the Fe contamination, which is reduced to ∼1 × 10 eVcm after the hydrogenation treatment. The charge neutral level, which shifts toward the conduction band after the Fe contamination, is reversed after hydrogenation. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

High efficiency commercial silicon solar cell technologies are often fabricated on n-type wafers to avoid light-induced degradation and other recombination centres that are observed in boron-doped Czochralski silicon. The advanced cell structures often feature the p–n junction on the rear of the device and require high bulk lifetimes in order to achieve high efficiencies. However n-type Czochralski silicon is still subject to a range of impurity related defects which can substantially reduce the lifetime of such material. In this work, large improvements in bulk lifetimes were demonstrated on standard commercial grade n-type Czochralski silicon from values in the range of 90–190 μs to values of 3.4–4.9 ms through the use of a short, low temperature hydrogen passivation process only using atomic hydrogen released from layers of silicon oxynitride grown by plasma enhanced chemical vapour deposition. The large improvements suggest that wafers with inherent low lifetimes, often deemed unsuitable to achieve high efficiencies, could in fact be compatible with the use of advanced cell architectures, to realise cell efficiencies over 24%. Oxygen precipitates are one type of impurity related defect which can cause substantial lifetime and efficiency limitations in both n- and p-type Czochralski silicon solar cells. An advanced hydrogenation process incorporating minority carrier injection was observed to lead to the complete electrical deactivation of the recombination activity of the defects. Furthermore, the passivation was retained throughout the remainder of the fabrication sequence and hence, no recombination activity from oxygen precipitates was evident on finished devices. [ABSTRACT FROM AUTHOR]

Using density functional theory-based calculation, we have investigated the structural and electrical properties such as atomic structure, energetics, band gap, and work function of various armchair and zigzag CdS nanoribbons. Our study establishes that the armchair nanoribbons are more favorable compared to zigzag nanoribbons. It also reveals that both the armchair and zigzag nanoribbons become more stable upon hydrogen passivation at the edges. With regard to band gap, it is found that all the armchair nanoribbons are semiconducting in nature and their band gap decreases smoothly with increasing ribbon width. On the other hand, the lower width zigzag nanoribbons turn out to be semiconducting and they undergo a metallic transition as width increases. The effect of hydrogen passivation on band gap is also investigated. We further study work functions of all nanoribbons, which is relevant to field emission applications. [ABSTRACT FROM AUTHOR]