کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1593648 1515675 2009 4 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Enhancement of laser-induced field emission in tungsten due to a metastable d band
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد دانش مواد (عمومی)
پیش نمایش صفحه اول مقاله
Enhancement of laser-induced field emission in tungsten due to a metastable d band
چکیده انگلیسی
A possible theory explaining the experimentally observed large enhancement of the field emission current from a tungsten needle exposed to a laser beam is presented. Calculations based on the density functional theory indicate a large density of 5d states and less dense 6p states above the Fermi level. The incident laser beam of 2.5 eV pumps the electrons to an unoccupied 6p band, some of which then de-excite to 5d states at lower energies, forming metastable states since the radiative decay from 5d states to the ground state 6s band is forbidden. On the other hand, the tunneling time from the metastable state is shorter than that from the ground state because of a smaller surface barrier, which may lead to the observed enhancement of the emitted current.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Solid State Communications - Volume 149, Issues 31–32, August 2009, Pages 1257-1260
نویسندگان
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