Self-aligned selective emitter plasma-etchback and passivation process for screen-printed silicon solar cells

Plasma-enhanced chemical vapor deposition (PECVD) is a cost-effective, performance-enhancing technique that can provide surface passivation and produce an effective antireflection coating layer at the same time. To gain the full benefit from improved emitter surface passivation on cell performance, it is necessary to tailor the emitter doping profile so that the emitter is lightly doped between the gridlines, but heavily doped under them. This selectively patterned emitter doping profile has historically been obtained by using expensive photolithographic or screen-printed alignment techniques and multiple high-temperature diffusion steps. We built on a self-aligned emitter etchback technique first described by Spectrolab. We included PECVD-nitride deposition because the low- recombination emitter produced by the etchback requires good surface passivation for improved cell performance. The nitride also provides a good antireflection coating. We studied whether plasma-etching techniques can use standard screen-printed gridlines at etch masks to form self-aligned, patterned-emitter profiles on multicrystalline (MC-Si) cells from Solarex Corp. This investigation determined that reactive ion etching (RIE) is compatible with using standard, commercial, screen printed gridlines as etch masks to form self- aligned, selectively-doped emitter profiles. This process results in reduced gridline contact resistance when followed by PECVD treatments, an undamaged emitter surface easily passivated by plasma-nitride, and a less heavily doped emitter between gridlines for reduced emitter recombination. This allows for heavier doping beneath the gridlines for even lower contact resistance, reduced contact recombination, and better bulk defect gettering. Our results found improvement of half a percentage point in cell efficiency when the self-aligned emitter etchback was combined with the PECVD-nitride surface passivation treatment

Plasma etching, texturing, and passivation of silicon solar cells

The authors improved a self-aligned emitter etchback technique that requires only a single emitter diffusion and no alignments to form self-aligned, patterned-emitter profiles. Standard commercial screen-printed gridlines mask a plasma-etchback of the emitter. A subsequent PECVD-nitride deposition provides good surface and bulk passivation and an antireflection coating. The authors used full-size multicrystalline silicon (mc-Si) cells processed in a commercial production line and performed a statistically designed multiparameter experiment to optimize the use of a hydrogenation treatment to increase performance. They obtained an improvement of almost a full percentage point in cell efficiency when the self-aligned emitter etchback was combined with an optimized 3-step PECVD-nitride surface passivation and hydrogenation treatment. They also investigated the inclusion of a plasma-etching process that results in a low-reflectance, textured surface on multicrystalline silicon cells. Preliminary results indicate reflectance can be significantly reduced without etching away the emitter diffusion

Optimization of plasma deposition and etching processes for commercial multicrystalline silicon solar cells

The authors conducted an investigation of plasma deposition and etching processes on full-size multicrystalline (mc-Si) cells processed in commercial production lines, so that any improvements obtained will be immediately relevant to the PV industry. In one case, the authors performed a statistically designed multiparameter experiment to determine the optimum PECVD-nitride deposition conditions specific to EFG silicon from ASE Americas, Inc. In a related effort, they studied whether plasma-etching techniques can use standard screen-printed gridlines as etch masks to form self-aligned, patterned-emitter profiles on mc-Si cells from Solarex Corp. Initial results found a statistically significant improvement of about half an absolute percentage point in cell efficiency when the self-aligned emitter etchback was combined with the PECVD-nitride surface passivation treatment. Additional improvement is expected when the successful bulk passivation treatment is also added to the process

ARIA 2016: Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma a

Measurement of the total cross section and ρ -parameter from elastic scattering in pp collisions at √s=13 TeV with the ATLAS detector

In a special run of the LHC with β⋆=2.5 km, proton–proton elastic-scattering events were recorded at s√=13 TeV with an integrated luminosity of 340 μb−1 using the ALFA subdetector of ATLAS in 2016. The elastic cross section was measured differentially in the Mandelstam t variable in the range from −t=2.5⋅10−4 GeV2 to −t=0.46 GeV2 using 6.9 million elastic-scattering candidates. This paper presents measurements of the total cross section σtot, parameters of the nuclear slope, and the ρ-parameter defined as the ratio of the real part to the imaginary part of the elastic-scattering amplitude in the limit t→0. These parameters are determined from a fit to the differential elastic cross section using the optical theorem and different parameterizations of the t-dependence. The results for σtot and ρ are σtot(pp→X)=104.7±1.1 mb ,ρ=0.098±0.011. The uncertainty in σtot is dominated by the luminosity measurement, and in ρ by imperfect knowledge of the detector alignment and by modelling of the nuclear amplitude.publishedVersio

The ATLAS Fast TracKer system

The ATLAS Fast TracKer (FTK) was designed to provide full tracking for the ATLAS high-level trigger by using pattern recognition based on Associative Memory (AM) chips and fitting in high-speed field programmable gate arrays. The tracks found by the FTK are based on inputs from all modules of the pixel and silicon microstrip trackers. The as-built FTK system and components are described, as is the online software used to control them while running in the ATLAS data acquisition system. Also described is the simulation of the FTK hardware and the optimization of the AM pattern banks. An optimization for long-lived particles with large impact parameter values is included. A test of the FTK system with the data playback facility that allowed the FTK to be commissioned during the shutdown between Run 2 and Run 3 of the LHC is reported. The resulting tracks from part of the FTK system covering a limited η-ϕ region of the detector are compared with the output from the FTK simulation. It is shown that FTK performance is in good agreement with the simulation

Precision measurement of the B0 meson lifetime using B0 → J/ψ K∗0 decays with the ATLAS detector

Abstract A measurement of the $$B^{0}$$ B 0 meson lifetime using $$B^{0} \rightarrow J/\psi K^{*0}$$ B 0 → J / ψ K ∗ 0 decays in data from 13  $$\text {TeV}$$ TeV proton–proton collisions with an integrated luminosity of $$140~\mathrm {fb^{-1}}$$ 140 fb - 1 recorded by the ATLAS detector at the LHC is presented. The measured effective lifetime is $$\tau = 1.5053\pm 0.0012~\mathrm {(stat.)} \pm 0.0035~\mathrm {(syst.)~ps}.$$ τ = 1.5053 ± 0.0012 ( stat . ) ± 0.0035 ( syst . ) ps . The average decay width extracted from the effective lifetime, using parameters from external sources, is $$\begin{aligned} \Gamma _d = 0.6639\pm 0.0005~\mathrm {(stat.)} \pm 0.0016~\mathrm {(syst.)}\\ \pm 0.0038~\text {(ext.)} \text {~ps}^{-1}, \end{aligned}$$ Γ d = 0.6639 ± 0.0005 ( stat . ) ± 0.0016 ( syst . ) ± 0.0038 (ext.) ps - 1 , where the uncertainties are statistical, systematic and from external sources. The earlier ATLAS measurement of $$\Gamma _s$$ Γ s in the $$B^{0}_{s} \rightarrow J/\psi \phi$$ B s 0 → J / ψ ϕ decay was used to derive a value for the ratio of the average decay widths $$\Gamma _d$$ Γ d and $$\Gamma _s$$ Γ s for $$B^{0}$$ B 0 and $$B^{0}_{s}$$ B s 0 mesons respectively, of $$\frac{\Gamma _d }{\Gamma _s } = 0.9905\pm 0.0022~\text {(stat.)} \pm 0.0036~\text {(syst.)} \pm 0.0057~\text {(ext.)}.$$ Γ d Γ s = 0.9905 ± 0.0022 (stat.) ± 0.0036 (syst.) ± 0.0057 (ext.) . The measured lifetime, average decay width and decay width ratio are in agreement with theoretical predictions and with measurements by other experiments. This measurement provides the most precise result of the effective lifetime of the $$B^{0}$$ B 0 meson to date. </jats:p

Deep generative models for fast photon shower simulation in ATLAS

The need for large-scale production of highly accurate simulated event samples for the extensive physics programme of the ATLAS experiment at the Large Hadron Collider motivates the development of new simulation techniques. Building on the recent success of deep learning algorithms, variational autoencoders and generative adversarial networks are investigated for modelling the response of the central region of the ATLAS electromagnetic calorimeter to photons of various energies. The properties of synthesised showers are compared with showers from a full detector simulation using geant4. Both variational autoencoders and generative adversarial networks are capable of quickly simulating electromagnetic showers with correct total energies and stochasticity, though the modelling of some shower shape distributions requires more refinement. This feasibility study demonstrates the potential of using such algorithms for ATLAS fast calorimeter simulation in the future and shows a possible way to complement current simulation techniques

Search for light long-lived neutral particles that decay to collimated pairs of leptons or light hadrons in pp collisions at s√ = 13 TeV with the ATLAS detector

A search for light long-lived neutral particles with masses in the O(MeV–GeV) range is presented. The analysis targets the production of long-lived dark photons in the decay of a Higgs boson produced via gluon–gluon fusion or in association with a W boson. Events that contain displaced collimated Standard Model fermions reconstructed in the calorimeter or muon spectrometer are selected in 139 fb−1 of s√ = 13 TeV pp collision data collected by the ATLAS detector at the LHC. Background estimates for contributions from Standard Model processes and instrumental effects are extracted from data. The observed event yields are consistent with the expected background. Exclusion limits are reported on the production cross-section times branching fraction as a function of the mean proper decay length cτ of the dark photon, or as a function of the dark-photon mass and kinetic mixing parameter that quantifies the coupling between the Standard Model and potential hidden (dark) sectors. A Higgs boson branching fraction above 1% is excluded at 95% CL for a Higgs boson decaying into two dark photons for dark-photon mean proper decay lengths between 10 mm and 250 mm and dark photons with masses between 0.4 GeV and 2 GeV