کد مقاله کد نشریه سال انتشار مقاله انگلیسی ترجمه فارسی نسخه تمام متن
5435678 1398118 2018 7 صفحه PDF ندارد دانلود رایگان
عنوان انگلیسی مقاله
In situ dynamic TEM characterization of unsteady crystallization during laser processing of amorphous germanium
ترجمه فارسی عنوان
خصوصیات کریستالیزاسیون ناپایدار در طول پردازش لیزر ژرمانیم آمورف در TEM
کلمات کلیدی
کریستالیزاسیون انفجاری؛ میکروسکوپ الکترونی انتقال (TEM)؛ مکانیسم تشکیل میکروارگانیسم؛
Explosive crystallization; In situ transmission electron microscopy (TEM); Microstructure formation mechanism;
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
چکیده انگلیسی

The unsteady propagation mechanism for the crystallization of amorphous germanium (a-Ge) was studied with in situ movie-mode dynamic transmission electron microscopy (MM-DTEM). Short laser pulses were used to heat sputter-deposited a-Ge films and the resulting crystallization process was imaged with up to 16 sequential 50 ns long electron pulses separated by a controlled delay that was varied between 0.5 and 5 μs The unsteady crystallization in the radial, net-growth direction was observed to occur at a decreasing rate of ∼1.5–0.2 m/s through a mechanism involving the formation of discrete ∼1.1 μm wide bands that grew with velocities of 9–12 m/s perpendicular to the radial direction and along the perimeter of the crystallized area. The crystallization rate and resulting microstructure were consistent with a liquid-mediated growth mechanism, which suggests that locally the band front reaches the amorphous melting temperature of Ge. A mechanism based on the notion of a critical temperature is proposed to explain the unsteady, banded behavior.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 143, 15 January 2018, Pages 13-19
نویسندگان
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