Key Success Factors and Future Perspective of Silicon-Based Solar Cells

Today, after more than 70 years of continued progress on silicon technology, about 85% of cumulative installed photovolatic (PV) modules are based on crystalline silicon (c-Si). PV devices based on silicon are the most common solar cells currently being produced, and it is mainly due to silicon technology that the PV has grown by 40% per year over the last decade. An additional step in the silicon solar cell development is ongoing, and it is related to a further efficiency improvement through defect control, device optimization, surface modification, and nanotechnology approaches. This paper attempts to briefly review the most important advances and current technologies used to produce crystalline silicon solar devices and in the meantime the most challenging and promising strategies acting to increase the efficiency to cost/ratio of silicon solar cells. Eventually, the impact and the potentiality of using a nanotechnology approach in a silicon-based solar cell are also described

Isotope and Quantum Effects in Vibrational State Distributions of Photodesorbed Ammonia

A marked quantum effect has been observed in the vibrational state distribution of photodesorbed ammonia. Namely, for quantum numbers larger than zero, symmetric and antisymmetric levels in the ν2 mode of the desorbed ammonia molecule are unequally populated. A strong propensity for symmetric levels is observed for NH3, whereas the reverse is found for ND3. Model calculations reproduce this effect. Moreover, it is found that the actual ratios probe the binding energy in the energetically less favorable inverted geometry with the H atoms pointing towards the surface

Assessment of the composition of Silicon-Rich Oxide films for photovoltaic applications by optical techniques

Abstract The deposition of sub-stoichiometric silicon rich oxide (SRO) is the first step to obtain well ordered silicon Quantum Dots (QDs) in a dielectric matrix. This structure is used also for third generation photovoltaic devices operating in a tandem architecture. A precise control and assessment of the stoichiometry of these films is crucial to tune the electrical and optical properties of the device. In this paper we discuss two optical techniques to assess the composition of such films and we compare their results

Physical determinants of Division 1 Collegiate basketball, Women’s National Basketball League and Women’s National Basketball Association athletes: with reference to lower body sidedness

In female basketball the assumed components of success include power, agility, and the proficiency at executing movements using each limb. However, the importance of these attributes in discriminating between playing levels in female basketball have yet to be determined. The purpose of this study was to compare lower body power, change of direction (COD) speed, agility, and lower-body sidedness between basketball athletes participating in Division 1 Collegiate basketball (United States), Women\u27s National Basketball League (WNBL) (Australia), and Women\u27s National Basketball Association (WNBA) (United States). Fifteen female athletes from each league (N = 45) completed a double and single leg counter-movement jump, static jump, drop jump, 5-0-5 COD Test, and an offensive and defensive Agility Test. One-way analysis of variance with post-hoc comparisons, were conducted to compare differences in physical characteristics (height, body mass, age) and performance outcomes (jump, COD, agility assessments) between playing levels. Separate dependent t-tests were performed to compare lower body sidedness (left vs. right lower-limbs) during the single-leg CMJ jumps (vertical jump height) and 5-0-5 COD test for each limb within each playing level. WNBA athletes displayed significantly greater lower body power (P = 0.01 - 0.03) compared to WNBL athletes, significantly faster COD speed (P = 0.02 - 0.03), and offensive and defensive agility performance (P = 0.02 - 0.03) compared to WNBL and Collegiate athletes. WNBL athletes also produced faster defensive agility performance compared to Collegiate athletes (P = 0.02). Further, WNBA and WNBL athletes exhibited reduced lower body sidedness compared to Collegiate athletes. These findings indicate the importance of lower body power, agility, and reduced lower body imbalances to execute more proficient on court movements, required to compete at higher playing levels. Copyright (C) 2017 by the National Strength & Conditioning Association

Growth and Characterization of Cu2Zn1-xFexSnS4 Thin Films for Photovoltaic Applications.

Photovoltaics is a promising technology to produce sustainable energy, thanks to the high amount of energy emitted by the sun. One way of having solar cells with low production costs is to apply thin-film technology and with earth-abundant raw materials. A keen interest is arising in kesterite compounds, which are chalcogenides composed of abundant and non-toxic elements. They have already achieved excellent performance at the laboratory level. Here, we report the synthesis and characterization of mixed chalcogenides based on copper, zinc, iron, and tin. Solutions have been studied with different zinc and iron ratios. The distortion of the elementary cell of kesterite increases with the addition of iron until a phase transition to stannite occurs. The process of synthesis and deposition proposed herein is cheap and straightforward, based on the sol-gel technique. These thin films are particularly attractive for use in cheap and easily processable solar cells. The synthesized layers have been characterized by X-ray diffraction, UV-Vis absorption, and Raman, X-ray photoelectron, and energy-dispersive X-ray spectroscopy measurements

Indium phosphide based membrane photodetector for optical interconnects on silicon

We have designed, fabricated and characterized an InP-based membrane photodetector on an SOI wafer containing a Si-wiring photonic circuit. New results on RF characterization up to 20 GHz are presented. The detector fabrication is compatible with wafer scale processing steps, guaranteeing compatibility towards future generation electronic IC processing

Hybrid sputtering/evaporation deposition of Cu(In,Ga)Se2 thin film solar cells

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The halo 3-point correlation function: a methodological analysis

Upcoming galaxy surveys will provide us with an unprecedented view of the Large -Scale Structure of the Universe and the realistic chance to extract valuable astrophysical and cosmological information from higher-order clustering statistics. This perspective poses new challenges, requiring both accurate and efficient estimators and a renewed assessment of possible systematic errors in the theoretical models and likelihood assumptions. This work investigates these issues in relation to the analysis of the 3-point correlation function (3PCF) in configuration space. We measure the 3PCF of 300 halo catalogs from the MINERVA simulations covering a total volume of 1000h-3Gpc3. Each 3PCF measurement includes all possible triangular configurations with sides between 20 and 130h-1 Mpc. In the first place, we test different estimates of the covariance matrix, a crucial aspect of the analysis. We compare the covariance computed numerically from the limited but accurate benchmark simulations set to the one obtained from 10000 approximate halo catalogs generated with the PINOCCHIO code. We demonstrate that the two numerically-estimated covariance matrices largely match, confirming the validity of approximate methods based on Lagrangian Perturbation Theory for generating mocks suitable for covariance estimation. We also compare the numerical covariance with a theoretical prediction in the Gaussian approximation. We find a good match between the two for separations above 40h-1 Mpc. We test the 3PCF tree-level model in Perturbation Theory. The model is adopted in a likelihood analysis aimed at the determination of bias parameters. We find that, for our sample of halos at redshift z = 1, the tree-level model performs well for separations r > 40h-1 Mpc. Results obtained with this scale cut are robust against different choices of covariance matrix. We compare to the analogous analysis of the halo bispectrum already presented in a previous publication, finding a remarkable agreement between the two statistics. We notice that such comparison relies, to the best of our knowledge for the first time, on a robust and consistent covariance estimate and on the inclusion of essentially all measurable configurations in Fourier as in configuration space. We then test different assumptions to build the model defining a robust combination of hypotheses that lead to unbiased parameter estimates. Our results confirm the importance of 3PCF, supplying a solid recipe for its inclusion in likelihood analyses. Moreover, it opens the path for further improvements, especially in modelling, to extract information from non-linear regimes