387 resultados para III-Nitride
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Codoping of p-type GaN nanowires with Mg and oxygen was investigated using first-principles calculations. The Mg becomes a deep acceptor in GaN nanowires with high ionization energy due to the quantum confinement. The ionization energy of Mg doped GaN nanowires containing passivated Mg-O complex decreases with increasing the diameter, and reduces to 300 meV as the diameter of the GaN nanowire is larger than 2.01 nm, which indicates that Mg-O codoping is suitable for achieving p-type GaN nanowires with larger diameters. The codoping method to reduce the ionization energy can be effectively used in other semiconductor nanostructures. (C) 2010 American Institute of Physics.
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Atomic configurations and formation energies of native defects in an unsaturated GaN nanowire grown along the [001] direction and with (100) lateral facets are studied using large-scale ab initio calculation. Cation and anion vacancies, antisites, and interstitials in the neutral charge state are all considered. The configurations of these defects in the core region and outermost surface region of the nanowire are different. The atomic configurations of the defects in the core region are same as those in the bulk GaN, and the formation energy is large. The defects at the surface show different atomic configurations with low formation energy. Starting from a Ga vacancy at the edge of the side plane of the nanowire, a N-N split interstitial is formed after relaxation. As a N site is replaced by a Ga atom in the suboutermost layer, the Ga atom will be expelled out of the outermost layers and leaves a vacancy at the original N site. The Ga interstitial at the outmost surface will diffuse out by interstitialcy mechanism. For all the tested cases N-N split interstitials are easily formed with low formation energy in the nanowires, indicating N-2 molecular will appear in the GaN nanowire, which agrees well with experimental findings.