Despite high demand for gold film nanostructuring, patterning gold at the nanoscale still presents considerable challenges for current foundry-compatible processes. Here, we present a method based on abrasive-free chemical mechanical planarization (CMP) to planarize nanostructured gold surfaces with high selectivity against SiO. The method is efficient in a damascene process and industry-compatible.
View Article and Find Full Text PDFChemical vapour deposition (CVD) synthesis of graphene on copper has been broadly adopted since the first demonstration of this process. However, widespread use of CVD-grown graphene for basic science and applications has been hindered by challenges with reproducibility and quality. Here we identify trace oxygen as a key factor determining the growth trajectory and quality for graphene grown by low-pressure CVD.
View Article and Find Full Text PDFChemical vapor deposition of CH4 on Ge(001) can enable anisotropic growth of narrow, semiconducting graphene nanoribbons with predominately smooth armchair edges and high-performance charge transport properties. However, such nanoribbons are not aligned in one direction but instead grow perpendicularly, which is not optimal for integration into high-performance electronics. Here, it is demonstrated that vicinal Ge(001) substrates can be used to synthesize armchair nanoribbons, of which ∼90% are aligned within ±1.
View Article and Find Full Text PDFWe report on real time observations of the sublimation of exfoliated black phosphorus layers throughout annealing using in situ low energy electron microscopy. We found that sublimation manifests itself above 375 ± 20 °C through the nucleation and expansion of asymmetric, faceted holes with the long axis aligned along the [100] direction and sharp tips defined by edges consisting of alternating (10) and (11) steps. This thermally activated process repeats itself via successive sublimation of individual layers.
View Article and Find Full Text PDFThe growth of the first ten layers of organic thin films on a smooth metallic substrate has been investigated in real-time using the model system PTCDA on Ag(111). The complex behaviour is comprehensively studied by electron microscopy, spectroscopy and diffraction in a combined PEEM/LEEM instrument revealing several new phenomena and yielding a consistent picture of this layer growth. PTCDA grows above room temperature in a Stranski-Krastanov mode, forming three-dimensional islands on a stable bi-layer, in competition with metastable 3rd and 4th layers.
View Article and Find Full Text PDFGraphene can be transformed from a semimetal into a semiconductor if it is confined into nanoribbons narrower than 10 nm with controlled crystallographic orientation and well-defined armchair edges. However, the scalable synthesis of nanoribbons with this precision directly on insulating or semiconducting substrates has not been possible. Here we demonstrate the synthesis of graphene nanoribbons on Ge(001) via chemical vapour deposition.
View Article and Find Full Text PDFThin layers of black phosphorus have recently raised interest owing to their two-dimensional (2D) semiconducting properties, such as tunable direct bandgap and high carrier mobilities. This lamellar crystal of phosphorus atoms can be exfoliated down to monolayer 2D-phosphane (also called phosphorene) using procedures similar to those used for graphene. Probing the properties has, however, been challenged by a fast degradation of the thinnest layers on exposure to ambient conditions.
View Article and Find Full Text PDFThe role of endomyocardial biopsy (EMB) in the diagnosis and treatment of adults presenting a newly unexplained cardiomyopathy remains controversial and the clinical indication varies among different centers. Furthermore, the choice of the ventricular site for EMB is still under debate. The right ventricular EMB is commonly used due to safety features and left ventricle (LV) EMB has not yet gained acceptance because of concerns about possible complications.
View Article and Find Full Text PDFA 24-year-old healthy man consulted to our center because of typical on-and-off chest-pain and an electrocardiogram showing ST-segment elevation in inferior leads. An urgent coronary angiography showed angiographically normal coronary arteries. Cardiovascular magnetic resonance imaging confirmed acute myocarditis.
View Article and Find Full Text PDFA systematic study has been conducted to investigate the role of hydrogen in the etching reaction of graphene films grown on copper foils. The results at 825 °C and 500 mTorr showed no evidence of graphene etching by purified ultrahigh purity (UHP)-grade hydrogen, whereas graphene films exposed to unpurified UHP-grade hydrogen were considerably etched due to the presence of oxygen or other oxidizing impurities. This finding reveals not only the major impact of oxidizing impurities in the graphene etching reaction, but also entails understanding and controlling the graphene chemical vapor deposition mechanism on copper substrates.
View Article and Find Full Text PDFGraphene field effect transistors (FETs) are extremely sensitive to gas exposure. Charge transfer doping of graphene FETs by atmospheric gas is ubiquitous but not yet understood. We have used graphene FETs to probe minute changes in electrochemical potential during high-purity gas exposure experiments.
View Article and Find Full Text PDFJ Obstet Gynaecol Can
January 2004
Objective: To review the use of hormonal replacement therapy (HRT) after treatment of breast cancer.
Options: The effect and role of estrogens on breast cancer.
Outcome: Improved health and quality of life for women with breast cancer.
Objective: The primary objective of this guideline is to provide Canadian physicians up-to-date, accurate information and recommendations regarding: i) impact of pregnancy and lactation on risk of breast cancer; ii) prognosis of breast cancer diagnosed during pregnancy and lactation; iii) risk of recurrence of breast cancer with the occurrence of subsequent pregnancies; iv) feasibility of breastfeeding and its impact on the prognosis of women with breast cancer.
Options: This guideline reviews evidence on whether pregnancy and breastfeeding change the lifetime risk for breast cancer in women, and whether breast cancer diagnosed during pregnancy or during lactation has a different prognosis. It offers the clinician advice on the diagnostic options to help identify breast cancer in pregnancy and/or during lactation, and offers evidence-based recommendations in managing an ongoing pregnancy and/or lactation when treatment for breast cancer is being planned.