High Efficiency Si Solar Cells Characterization Using

Abstract. Impedance Spectroscopy has been used to analyse commercial Si photovoltaic solar cells, to obtain information about minority carrier lifetimes, series and parallel resistances, and acceptor impurity densities. Silicon solar cells efficiencies ranging between 17 and 18% from different manufacturers have been analysed obtaining differences mainly in the electron lifetimes and doping densities. Relations between these parameters and DC curves are discussedMinisterio de Economía y Competitividad under project TEC2013-4835-

Short communication: Occurrence of angular leaf spot caused by Pseudocercospora griseola in Phaseolus vulgaris in Asturias, Spain

Angular leaf spot (ALS) symptoms were observed in 2015 in common bean fields at four locations in Asturias, NW Spain. This disease is frequent in tropical areas and we have no record of its presence in our region, at least in the last 30 years. However, since its detection its presence in the crops has been increasing. Symptoms were necrotic spots on leaves and reddish-brown to black circular spots on pods, stems, branches and petioles. The damage observed in the mentioned crops was highly variable (between 60% and 100% affected leaves), being most severe in crops where no agrochemical treatment were applied. Three strains were selected and identified based in morphological features as Pseudocercospora griseola. The ITS region was amplified by PCR obtaining a sequence that was identical for the three isolates (Acc. No. LT222499). This sequence showed 99-100% similarity with those deposited in databases corresponding to P. griseola. To fulfill Koch's postulates, a pathogenicity test was carried out in two common bean cultivars (‘Andecha’ and ‘Maruxina’). P. griseola was re-isolated from inoculated plants and not from control plants. In cv. ‘Andecha’, chlorosis was observed in all the inoculated plants, before the appearance of spots. Consequently this is the first confirmed report of this pathogen in our region

Effects of introgressed 4Nv Aegilops ventricosa chromosome on yield and yield components in bread wheat.

Effects of introgressed 4Nv Aegilops ventricosa chromosome on yield and yield components in bread whea

A novel growth method to improve the quality of GaAs nanowires grown by Ga-assisted chemical beam epitaxy

The successful synthesis of high crystalline quality and high aspect ratio GaAs nanowires (NWs) with a uniform diameter is needed to develop advanced applications beyond the limits established by thin film and bulk material properties. Vertically aligned GaAs NWs have been extensively grown by Ga-assisted vapor–liquid–solid (VLS) mechanism on Si(111) substrates, and they have been used as building blocks in photovoltaics, optoelectronics, electronics, and so forth. However, the nucleation of parasitic species such as traces and nanocrystals on the Si substrate surface during the NW growth could affect significantly the controlled nucleation of those NWs, and therefore the resulting performance of NW-based devices. Preventing the nucleation of parasitic species on the Si substrate is a matter of interest, because they could act as traps for gaseous precursors and/or chemical elements during VLS growth, drastically reducing the maximum length of grown NWs, affecting their morphology and structure, and reducing the NW density along the Si substrate surface. This work presents a novel and easy to develop growth method (i.e., without using advanced nanolithography techniques) to prevent the nucleation of parasitic species, while preserving the quality of GaAs NWs even for long duration growths. GaAs NWs are grown by Ga-assisted chemical beam epitaxy on oxidized Si(111) substrates using triethylgallium and tertiarybutylarsine precursors by a two-step-based growth method presented here; this method includes a growth interruption for an oxidation on air between both steps of growth, reducing the nucleation of parasitic crystals on the thicker SiOx capping layer during the second and longer growth step. VLS conditions are preserved overtime, resulting in a stable NW growth rate of around 6 μm/h for growth times up to 1 h. Resulting GaAs NWs have a high aspect ratio of 85 and average radius of 35 nm. We also report on the existence of characteristic reflection high-energy electron diffraction patterns associated with the epitaxial growth of GaAs NWs on Si(111) substrates, which have been analyzed and compared to the morphological characterization of GaAs NWs grown for different times under different conditions

Photodetector Fabrication by Dielectrophoretic Assembly of GaAs Nanowires Grown by a Two-steps Method

GaAs nanowires (NWs) are promising advanced materials for the development of high performance photodetectors in the visible and infrared range. In this work, we optimize the epitaxial growth of GaAs NWs compared to conventional procedures, by introducing a novel two-steps growth method that exhibits an improvement of the resulting NW aspectratio and an enhancement of the NW growth rate. Moreover, we investigate the contactless manipulation of NWs using non-uniform electric fields to assemble a single GaAs NW on conductive electrodes, resulting in assembly yields above 90%/site and an alignment yields of around 95%. The electrical characteristics of the dielectrophoretic contact formed between the NW and the electrode have been measured, observing that the use of n-type Al-doped ZnO (AZO) as electrode material for NW alignment produces Schottky barrier contacts with the GaAs NW body. Moreover, our results show the fast fabrication of diodes with rectifying characteristics due to the formation of a low-resistance contact between the Ga catalytic droplet at the tip of the NW and the AZO electrode. The current-voltage measurements of a single GaAs NW diode under different illumination conditions show a strong light responsivity of the forward bias characteristic mainly produced by a change on the series resistance

Antitumour activity of neratinib in patients with HER2-mutant advanced biliary tract cancers

Antitumour activity; Neratinib; Biliary tract cancersActividad antitumoral; Neratinib; Cánceres de vías biliaresActivitat antitumoral; Neratinib; Càncers de vies biliarsHER2 mutations are infrequent genomic events in biliary tract cancers (BTCs). Neratinib, an irreversible, pan-HER, oral tyrosine kinase inhibitor, interferes with constitutive receptor kinase activation and has activity in HER2-mutant tumours. SUMMIT is an open-label, single-arm, multi-cohort, phase 2, ‘basket’ trial of neratinib in patients with solid tumours harbouring oncogenic HER2 somatic mutations (ClinicalTrials.gov: NCT01953926). The primary objective of the BTC cohort, which is now complete, is first objective response rate (ORR) to neratinib 240 mg orally daily. Secondary objectives include confirmed ORR, clinical benefit rate, progression-free survival, duration of response, overall survival, safety and tolerability. Genomic analyses were exploratory. Among 25 treatment-refractory patients (11 cholangiocarcinoma, 10 gallbladder, 4 ampullary cancers), the ORR is 16% (95% CI 4.5–36.1%). The most common HER2 mutations are S310F (n = 11; 48%) and V777L (n = 4; 17%). Outcomes appear worse for ampullary tumours or those with co-occurring oncogenic TP53 and CDKN2A alterations. Loss of amplified HER2 S310F and acquisition of multiple previously undetected oncogenic co-mutations are identified at progression in one responder. Diarrhoea is the most common adverse event, with any-grade diarrhoea in 14 patients (56%). Although neratinib demonstrates antitumour activity in patients with refractory BTC harbouring HER2 mutations, the primary endpoint was not met and combinations may be explored.The SUMMIT trial was sponsored/funded by Puma Biotechnology, Inc. Investigators from MSKCC who participated in the trial were also supported in part by a Cancer Center Support Grant (P30 CA008748) and Cycle for Survival. Puma Biotechnology, Inc was involved in the following: study design; data collection, analysis and interpretation of the data; writing of the report; the decision to submit the article for publication. The authors would like to thank all patients and their families for participating in the SUMMIT trial. The authors acknowledge David Hyman (Memorial Sloan Kettering), Richard Bryce (Puma Biotechnology), and Alshad Lalani (Puma Biotechnology) for their important contributions to the original SUMMIT study design, oversight, and interpretation, and Feng Xu (Puma Biotechnology) and Jane Liang (Puma Biotechnology) for statistical and programming support. The authors also thank Lee Miller and Deirdre Carman (Miller Medical Communications Ltd) for medical writing/editing assistance, which was funded by Puma Biotechnology, Inc

Single GaAs nanowire based photodetector fabricated by dielectrophoresis

Mechanical manipulation of nanowires (NWs) for their integration in electronics is still problematic because of their reduced dimensions, risking to produce mechanical damage to the NW structure and electronic properties during the assembly process. In this regard, contactless NW manipulation based methods using non-uniform electric fields, like dielectrophoresis (DEP) are usually much softer than mechanical methods, offering a less destructive alternative for integrating nanostructures in electronic devices. Here, we report a feasible and reproducible dielectrophoretic method to assemble single GaAs NWs (with radius 35–50 nm, and lengths 3–5 μm) on conductive electrodes layout with assembly yields above 90% per site, and alignment yields of 95%. The electrical characteristics of the dielectrophoretic contact formed between a GaAs NW and conductive electrodes have been measured, observing Schottky barrier like contacts. Our results also show the fast fabrication of diodes with rectifying characteristics due to the formation of a low-resistance contact between the Ga catalytic droplet at the tip of the NW when using Al doped ZnO as electrode. The current-voltage characteristics of a single Ga-terminated GaAs NW measured in dark and under illumination exhibit a strong sensitivity to visible light under forward bias conditions (around two orders of magnitude), mainly produced by a change on the series resistance of the device

4-[(1,3-Dioxo-2,3-dihydro-1H-benzo[de]isoquinolin-2-yl)meth­yl]-N′-[(E)-4-nitro­benzyl­idene]benzene­sulfono­hydrazide dimethyl sulfoxide monosolvate

The mol­ecular structure of the title compound, C26H18N4O6S·C2H6OS, shows an E conformation of the hydrazone double bond. The presence of a methyl­ene group between the benzo[de]isoquinoline and benzene­sulfonyl moieties allows the 4-nitro­phenyl ring and the benzo[de]isoquinoline system to be parallel with respect to each other, so that the mol­ecule adopts a U-shaped spatial conformation. The dihedral angle between mean planes of these aromatic groups is 4.4 (1)°. This special arrangement enables neighboring mol­ecules to be inter­calated, forming slipped π–π inter­actions [centroid–centroid distance = 3.535 (2) Å] between the 4-nitro­phenyl and benzo[de]isoquinoline groups and point-to-face C—H⋯π inter­actions between the benzo[de]isoquinoline and benzene­sulfonyl aromatic systems. In addition, the crystal packing also features an inter­molecular N—H⋯O inter­action involving the amine group and the dimethyl sulfoxide solvent mol­ecule

Growth of silicon- and carbon-doped GaAs by chemical beam epitaxy using H2-diluted DTBSi and CBr4 precursors

A wide range of n- and p-type doping levels in GaAs layers grown by chemical beam epitaxy is achieved by using H2-diluted DTBSi and CBr4 as gas precursors for Si and C, respectively. We show that the doping level can be varied by modifying either the concentration or the flux of the diluted precursor. Specifically, we demonstrate carrier concentrations of 7.8 × 1017 –1.4 × 1019 cm−3 for Si, and 1 × 1017 –3.8 × 1020 cm−3 for C, as determined by Hall effect measurements. The dependence of Si incorporation on the diluted-precursor flux is found to be linear. In contrast, we observe a superlinear behavior for C doping. The dependence of the electron and hole mobility values on the carrier concentration as well as the analysis of the layers by low-temperature (12 K) photoluminescence spectroscopy indicate that the use of H2 for diluting DTBSi or CBr4 has no effect on the electrical and optical properties of GaAsThis work was supported by the former Ministerio de Ciencia, Innovación y Universidades under Project No. TEC2016-78433-R and the current Ministerio de Ciencia e Innovación under Project No. PID2020-114280RB-I00. S. Fernández-Garrido and N. López acknowledge the final support received through the Spanish program Ramón y Cajal (co-financed by the European Social Fund) under Grants No. RYC2016-19509 and RYC-2016-20588, respectively, from the former Ministerio de Ciencia, Innovación y Universidades. N. López also acknowledges the funding received through the European ERC Starting Grant No. 75888