Science and Technology Review October/November 2010 (open access)

Science and Technology Review October/November 2010

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Date: September 13, 2010
Creator: Blobaum, K. J.
System: The UNT Digital Library
Efficiency Improvement of Nitride-Based Solid State Light Emitting Materials -- CRADA Final Report (open access)

Efficiency Improvement of Nitride-Based Solid State Light Emitting Materials -- CRADA Final Report

The development of In{sub x}Ga{sub 1-x} N/GaN thin film growth by Molecular Beam Epitaxy has opened a new route towards energy efficient solid-state lighting. Blue and green LED's became available that can be used to match the whole color spectrum of visible light with the potential to match the eye response curve. Moreover, the efficiency of such devices largely exceeds that of incandescent light sources (tungsten filaments) and even competes favorably with lighting by fluorescent lamps. It is, however, also seen in Figure 1 that it is essential to improve on the luminous performance of green LED's in order to mimic the eye response curve. This lack of sufficiently efficient green LED's relates to particularities of the In{sub x}Ga{sub 1-x}N materials system. This ternary alloy system is polar and large strain is generated during a lattice mismatched thin film growth because of the significantly different lattice parameters between GaN and InN and common substrates such as sapphire. Moreover, it is challenging to incorporate indium into GaN at typical growth temperatures because a miscibility gap exists that can be modified by strain effects. As a result a large parameter space needs exploration to optimize the growth of In{sub x}Ga{sub 1-x}N and …
Date: May 13, 2010
Creator: Kisielowski, Christian & Weber, Eicke
System: The UNT Digital Library
Emergency Communications: Broadband and the Future of 911 (open access)

Emergency Communications: Broadband and the Future of 911

This report discusses the Summary of 911 Legislation and Policy, Funding and Grants and National Broadband Plan.
Date: December 13, 2010
Creator: Moore, Linda K.
System: The UNT Digital Library