M. Ohtsu; T. Kawazoe
Abstract
This paper reviews basic research and technical developments on silicon (Si) light-emitting diodes (Si-LEDs) fabricated by using a novel dressed-photon–phonon (DPP)-assisted annealing method. These devices exhibit unique light emission spectral profiles in the wavelength range 900–2500 nm, ...
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This paper reviews basic research and technical developments on silicon (Si) light-emitting diodes (Si-LEDs) fabricated by using a novel dressed-photon–phonon (DPP)-assisted annealing method. These devices exhibit unique light emission spectral profiles in the wavelength range 900–2500 nm, including novel photon breeding features. The highest optical output power demonstrated was as high as 2.0 W. It is pointed out that boron (B) atoms, serving as p-type dopants, formed pairs whose length was three-times the lattice constant of the host Si crystal. These B atom pairs are the origin of the photon breeding. It is pointed out that photon breeding took place with respect to photon spin. Furthermore, recent measurements show that the B atom pairs tend to form a chain-like configuration. Copyright © VBRI Press.
Venu H. Mankad; Sanjeev K. Gupta;Prafulla K. Jha
Abstract
The size dependent vibrational and thermodynamical properties of Zinc Oxide Nanowire (ZnO NWs) along with its bulk counterparts has been studied using the first principles calculations within density functional theory. The thermodynamical parameters such as specific heat at constant volume, entropy, ...
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The size dependent vibrational and thermodynamical properties of Zinc Oxide Nanowire (ZnO NWs) along with its bulk counterparts has been studied using the first principles calculations within density functional theory. The thermodynamical parameters such as specific heat at constant volume, entropy, internal energy and Helmholtz energy as function of temperature for the different size of nanowires are obtained and compared with the bulk ZnO in wurtzite phase. We address the effects of structural confinement on the phonon dispersion, vibrational density of states and qualitatively on the sound velocities and thermal conductance. The phonon dispersion curves for considered ZnO nanowires and its bulk counterpart indicates dynamical stability. The band gap increases from bulk to nanowire and an inverse size dependency in the case of nanowires arising due to quantum confinement. The analysis of bands character in context of growth characteristics and thermodynamical properties are also discussed. Our findings will give some reference to the insight understanding of the electronic, vibrational and thermodynamical properties of size orientation dependent ZnO nanowire.
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