29 research outputs found
Origin of the n-type conductivity of InN: the role of positively charged dislocations
As-grown InN is known to exhibit high unintentional n-type conductivity. Hall measurements from a range of high-quality single-crystalline epitaxially grown InN films reveal a dramatic reduction in the electron density (from low 1019 to low 1017 cm–3) with increasing film thickness (from 50 to 12 000 nm). The combination of background donors from impurities and the extreme electron accumulation at InN surfaces is shown to be insufficient to reproduce the measured film thickness dependence of the free-electron density. When positively charged nitrogen vacancies (VN+) along dislocations are also included, agreement is obtained between the calculated and experimental thickness dependence of the free-electron concentration
Valence band offset of InN/AlN heterojunctions measured by X-ray photoelectron spectroscopy
The valence band offset of wurtzite-InN/AlN (0001) heterojunctions is determined by x-ray photoelectron spectroscopy to be 1.52±0.17 eV. Together with the resulting conduction band offset of 4.0±0.2 eV, a type-I heterojunction forms between InN and AlN in the straddling arrangement
Surface electronic properties of undoped InAlN alloys
The variation in surface electronic properties of undoped c-plane InxAl1−xN alloys has been investigated across the composition range using a combination of high-resolution x-ray photoemission spectroscopy and single-field Hall effect measurements. For the In-rich alloys, electron accumulation layers, accompanied by a downward band bending, are present at the surface, with a decrease to approximately flatband conditions with increasing Al composition. However, for the Al-rich alloys, the undoped samples were found to be insulating with approximate midgap pinning of the surface Fermi level observed
Transition from electron accumulation to depletion at InGaN surfaces
The composition dependence of the Fermi-level pinning at the oxidized (0001) surfaces of n-type InxGa1−xN films (0<=x<=1) is investigated using x-ray photoemission spectroscopy. The surface Fermi-level position varies from high above the conduction band minimum (CBM) at InN surfaces to significantly below the CBM at GaN surfaces, with the transition from electron accumulation to depletion occurring at approximately x=0.3. The results are consistent with the composition dependence of the band edges with respect to the charge neutrality level
ACC/AHA/SCAI 2005 Guideline Update for Percutaneous Coronary Intervention - Summary article: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/SCAI Writing Committee to Update the 200
ACC/AHA/SCAI 2005 Guideline Update for Percutaneous Coronary Intervention - Summary article: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/SCAI Writing Committee to Update the 2001 Guidelines for Percutaneous Coronary Intervention)
The American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions (ACC/AHA/SCAI) 2005 Guideline Update for Percutaneous Coronary Intervention (PCI) contains changes in the recommendations, along with supporting text. For the purpose of comparison, this summary contains a list of the updated recommendations (middle column) alongside a list of the 2001 recommendations (left column), with each set accompanied by a comment (right column) that provides the rationale for the changes, additions, or deletions (see Table 1). References that support either the 2001 recommendations that have changed or the new or revised recommendations are cited in parentheses at the end of each recommendation or comment. A list of abbreviations is included in the Appendix. The reader is referred to the full-text guideline posted on the World Wide Web sites of the ACC, the AHA, and the SCAI for a more detailed explanation of the changes discussed here. Please note that we have changed the table of contents headings in the 2001 ACC/AHA Guidelines for Percutaneous Coronary Intervention from roman numerals to unique identifying numbers
ACC/AHA/SCAI 2005 guideline update for percutaneous coronary intervention: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/SCAI Writing Committee to Update the 2001 Guidelines for Percutaneous Coronary Intervention)
"The ACC/AHA Task Force on Practice Guidelines was formed to gather information and make recommendations about appropriate use of technology for the diagnosis and treatment of patients with cardiovascular disease. Percutaneous coronary interventions (PCIs) are an important group of technologies in this regard. Although initially limited to balloon angioplasty and termed percutaneous transluminal coronary angioplasty (PTCA), PCI now includes other new techniques capable of relieving coronary narrowing. Accordingly, in this document, implantation of intracoronary stents and other catheter-based interventions for treating coronary atherosclerosis are considered components of PCI. In this context, PTCA will be used to refer to those studies using only balloon angioplasty, whereas PCI will refer to the broader group of percutaneous techniques. These new technologies have impacted the effectiveness and safety profile initially established for balloon angioplasty. Moreover, additional experience has been gained in the use of adjunctive pharmacological treatment with glycoprotein (GP) IIb/IIIa receptor antagonists and the use of bivalirudin, thienopyridines, and drug-eluting stents (DES). In addition, since publication of the guidelines in 2001, greater experience in the performance of PCI in patients with acute coronary syndromes and in community hospital settings has been gained. In view of these developments, an update of these guidelines e168 Circulation February 21, 2006 is warranted. This document reflects the opinion of the ACC/AHA/SCAI writing committee charged with updating the 2001 guidelines for PCI (1).
ACC/AHA/SCAI 2005 guideline update for percutaneous coronary intervention - Summary article: A report of the American College of Cardiology/American Heart Association Task Force on practice guidelines (ACC/AHA/SCAI Writing Committee to update the 2001 guidelines for Percutaneous Coronary Intervention)
The American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions (ACC/AHA/SCAI) 2005 Guideline Update for Percutaneous Coronary Intervention (PCI) contains changes in the recommendations, along with supporting text. For the purpose of comparison, this summary contains a list of the updated recommendations (middle column) alongside a list of the 2001 recommendations (left column), with each set accompanied by a comment (right column) that provides the rationale for the changes, additions, or deletions (see Table 1).References that support either the 2001 recommendations that have changed or the new or revised recommendations are cited in parentheses at the end of each recommendation or comment. A list of abbreviations is included in the Appendix. The reader is referred to the full-text guideline posted on the World Wide Web sites of the ACC, the AHA, and the SCAI for a more detailed explanation of the changes discussed here. Please note that we have changed the table of contents headings in the 2001 ACC/AHA Guidelines for Percutaneous Coronary Intervention from roman numerals to unique identifying numbers
The influence of conduction band plasmons on core-level photoemission spectra of InN
The core-level lineshape in photoemission spectra of InN is studied by high-resolution X-ray photoemission spectroscopy. The In 3d and N 1s core-levels are asymmetric, displaying a high binding energy tail which is attributed to inelastic losses to and/or screening by conduction band plasmons in the accumulation layer present at InN surfaces. The extent of the asymmetric tail decreases with decreasing surface Fermi level position associated with a lower density of electrons in the accumulation layer. (C) 2008 Elsevier B.V. All rights reserved