Fabrication of quantum emitters in aluminum nitride by Al-ion implantation and thermal annealing

Single-photon emitters (SPEs) within wide-bandgap materials represent an appealing platform for the development of single-photon sources operating at room temperatures. Group III-nitrides have previously been shown to host efficient SPEs, which are attributed to deep energy levels within the large bandgap of the material, in a configuration that is similar to extensively investigated color centers in diamond. Anti-bunched emission from defect centers within gallium nitride and aluminum nitride (AlN) have been recently demonstrated. While such emitters are particularly interesting due to the compatibility of III-nitrides with cleanroom processes, the nature of such defects and the optimal conditions for forming them are not fully understood. Here, we investigate Al implantation on a commercial AlN epilayer through subsequent steps of thermal annealing and confocal microscopy measurements. We observe a fluence-dependent increase in the density of the emitters, resulting in the creation of ensembles at the maximum implantation fluence. Annealing at 600 °C results in the optimal yield in SPEs formation at the maximum fluence, while a significant reduction in SPE density is observed at lower fluences. These findings suggest that the mechanism of vacancy formation plays a key role in the creation of the emitters and open enticing perspectives in the defect engineering of SPEs in solid state

Religious extremism: The good, the bad, and the deadly

This paper challenges conventional views of violent religious extremism, particularly those that emphasize militant theology. We offer an alternative analysis that helps explain the persistent demand for religion, the different types of religions that naturally arise, and the special attributes of the “sectarian” type. Sects are adept at producing club goods – both spiritual and material. Where governments and economies function poorly, sects often become major suppliers of social services, political action, and coercive force. Their success as providers is much more due to the advantages of their organizational structure than it is to their theology. Religious militancy is most effectively controlled through a combination of policies that raise the direct costs of violence, foster religious competition, improve social services, and encourage private enterprise. Copyright Springer Science+Business Media B.V. 2006Econoimcs of religion, Religious violence, Extremism, Sectarianism, Terrorism, Suicide-bombing, Rational choice,