Engineering the composition, morphology, and optical properties of InAsSb nanostructures via graded growth technique

Graded growth technique is utilized to realize the control over the composition, morphology, and optical properties of self-assembled InAsSb/InGaAs/InP nanostructures. By increasing the initial mole fraction of the Sb precursor during the graded growth of InAsSb, more Sb atoms can be incorporated into the InAsSb nanostructures despite the same Sb mole fraction averaged over the graded growth. This leads to a shape change from dots to dashes/wires for the InAsSb nanostructures. As a result of the composition and morphology change, photoluminescence from the InAsSb nanostructures shows different polarization and temperature characteristics. This work demonstrates a technologically important technique—graded growth, to control the growth and the resultant physical properties of self-assembled semiconductor nanostructures.Financial support from Australian Research Council is gratefully acknowledged

Multiple wavelength InGaAs quantum dot lasers using selective area epitaxy

The authors demonstrate multiple wavelength lasers fabricated from InGaAsquantum dots. Selective area epitaxy is used to grow the active region, consisting of five layer stack of InGaAsquantum dots with different band gapenergies in selected regions of the substrate, for fabrication of the lasers. The mechanism responsible for engineering of the band gap of quantum dots is discussed. The performance of the selectively grown lasers is compared to the lasers fabricated from structures grown in a standard, nonselective area growth process.The Australian Research Council is gratefully acknowledged for financial support

The state of commercial augmentative biological control: plenty of natural enemies, but a frustrating lack of uptake

Augmentative biological control concerns the periodical release of natural enemies. In com- mercial augmentative biological control, natural enemies are mass-reared in biofactories for release in large numbers to obtain an immediate control of pests. The history of commercial mass production of natural enemies spans a period of roughly 120 years. It has been a successful, environmentally and eco- nomically sound alternative for chemical pest control in crops like fruit orchards, maize, cotton, sugar cane, soybean, vineyards and greenhouses. Currently, aug- mentative biological control is in a critical phase, even though during the past decades it has moved from a cottage industry to professional production. Many efficient species of natural enemies have been discovered and 230 are commercially available today. The industry developed quality control guidelines, mass production, shipment and release methods as well as adequate guidance for farmers. However, augmentative biological control is applied on a frustratingly small acreage. Trends in research and application are reviewed, causes explaining the limited uptake are discussed and ways to increase application of augmentative biological control are explored

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

Gender – Merely a “Social Fact”? : The Construction of Neo-Authoritarian Us/Them Dichotomies

That gender cannot be reduced to an ahistorical fact is a widely researched insight of multidisciplinary gender studies. In theory as well as in political practice gender is thus generally understood as a post- essentialist, reflexive, and contingent concept. Against this backdrop the essay asks for the German context in what way and with which intentions, neo-authoritarian discourses and movements explicitly not only reject, attack and defame gender as concept, but also reclaim it. I will argue that under the cipher ‘anti-genderism’, a discourse has been formed that can first be described as a neo-fundamentalist discourse and that is secondly explicitly used to construct racist, neo-authoritarian us/them-dichotomies. The so called anti-gender forces become thus identifiable as the element of a dispositif, which is at the core and subject to further clarification of anti-democratic nature

Coloured Vowels:Wittgenstein on Synaesthesia and Secondary Meaning

The aim of this article is to give both a sustained interpretation of Wittgenstein's obscure remarks on the experience of meaning of language, synthaesthesia and secondary use and to apply his insights to recent philosophical discussions about synthaesthesia. I argue that synthaesthesia and experience of meaning are conceptually related to aspect-seeing. The concept of aspect-seeing is not reducible to either seeing or imaging but involves a modified notion of experience. Likewise, synthaesthesia involves a modified notion of experience. In particular, the concept of synthaesthesia involves a secondary use of 'experience' and hence is intrinsically dependent on the primary use of language. Recent discussions tend to overlook this distinction between the primary and secondary use of language