4,842 research outputs found
Intermixing of InGaAs/GaAs quantum wells and quantum dots using sputter-deposited silicon oxynitride capping layers
Various approaches can be used to selectively control the amount of intermixing in III-Vquantum well and quantum dotstructures. Impurity-free vacancy disordering is one technique that is favored for its simplicity, however this mechanism is sensitive to many experimental parameters. In this study, a series of silicon oxynitride capping layers have been used in the intermixing of InGaAs/GaAs quantum well and quantum dotstructures. These thin films were deposited by sputter deposition in order to minimize the incorporation of hydrogen, which has been reported to influence impurity-free vacancy disordering. The degree of intermixing was probed by photoluminescence spectroscopy and this is discussed with respect to the properties of the SiOxNyfilms. This work was also designed to monitor any additional intermixing that might be attributed to the sputtering process. In addition, the high-temperature stress is known to affect the group-III vacancy concentration, which is central to the intermixing process. This stress was directly measured and the experimental values are compared with an elastic-deformation model.This work has been made possible with access to the
ACT Node of the Australian National Fabrication Facility and
through the financial support of the Australian Research
Council
GeV Scale Asymmetric Dark Matter from Mirror Universe: Direct Detection and LHC Signatures
Mirror universe is a fundamental way to restore parity symmetry in weak
interactions. It naturally provides the lightest mirror nucleon as a unique
GeV-scale asymmetric dark matter particle candidate. We conjecture that the
mirror parity is respected by the fundamental interaction Lagrangian, and its
possible soft breaking arises only from non-interaction terms in the
gauge-singlet sector. We realize the spontaneous mirror parity violation by
minimizing the vacuum Higgs potential, and derive the corresponding Higgs
spectrum. We demonstrate that the common origin of CP violation in the visible
and mirror neutrino seesaws can generate the right amount of matter and mirror
dark matter via leptogenesis. We analyze the direct detections of GeV-scale
mirror dark matter by TEXONO and CDEX experiments. We further study the
predicted distinctive Higgs signatures at the LHC.Comment: 16pp. Plenary talk presented by HJH at the International Symposium on
Cosmology and Particle Astrophysics (CosPA2011). To appear in the conference
proceedings of IJMP. Minor refinement
Spatially resolved characterization of InGaAs/GaAs quantum dot structures by scanning spreading resistance microscopy
Cross-sectional scanning spreading resistance microscopy (SSRM) is used to investigate stacked InGaAs/GaAs quantum dot(QD)structures with different doping schemes. Spatially resolved imaging of the QDs by SSRM is demonstrated. The SSRM contrast obtained for the QD layers is found to depend on doping in the structure. In the undoped structures both QD-layers and QDs within the layers could be resolved, while in the dopedstructures the QD layers appear more or less uniformly broadened. The origin of the SSRM contrast in the QD layer in the different samples is discussed and correlated with doping schemes.T. Hakkarainen, O. Douhéret, and S. Anand would like
to acknowledge the Swedish Research Council VR for fi-
nancial support and the Kurt-Alice Wallenberg KAW foundation
for financing the microscope. L. Fu, H. H. Tan, and C.
Jagadish would like to acknowledge the Australian Research
Council ARC for financial support and Australian National
Fabrication Facility ANFF for access to the facilities
The Critical Success Factors and Integrated Model for Implementing E-business in Taiwanâs SMEs
Purpose - To date, identifying barriers and critical success factors (CSFs) and integrating business model in implementing e-business for SMEs have not been systematically investigated. Few existing studies have derived their CSFs and business model from large companies\u27 perspectives and have not considered the needs of integration for smaller businesses. This paper is aimed to bridge this gap.
Design/methodology/approach - Existing studies on CSFs and e-business model were reviewed and their limitations were identified. By integrating insights drawn from these studies as well as adding some new factors, the author proposed a set of 18 CSFs which is believed to be more useful for SMEs. The importance of the proposed CSFs was theoretically discussed and justified. In addition, a case study was conducted to evaluate the extent of success of this proposition.
Findings - The overall results from the case study assessment were positive, thus reflecting the appropriateness of the proposed CSFs and integrated model.
Practical implications - The set of CSFs and integrated model can act as a list of items and an easy to follow model for SMEs to address when adopting e-business. This helps to ensure that the essential issues and factors are covered during implementation. For academics, it provides a common language for them to discuss and study the factors crucial for the success of e-business in SMEs.
Originality/value - This study is probably the first to provide an integrative perspective of CSFs and integrated model for implementing e-business in the SME sector. It gives valuable information, which hopefully will help this business sector to accomplish e-business visions
Ediacaran Macro Body Fossils
This paper, Ediacaran Macro Body Fossils, reports a new discovery of well preserved three dimensional macro body fossils of the Ediacaran Period in central YunNan province in the People's Republic of China. These body fossils will enable more detailed and in-depth exploration of the evolution of multi-cellular macro organisms on this planet, whereas in the past, researches could only rely on cast or imprint fossils
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