分子動力學近年來被視為探討奈米尺度下機械性質有效的方法之ㄧ，其主要依循牛頓運動方程式，透過預測、修正等數值運算來得到各個時間步階下原子的位置、速度和加速度…等物理量。氮化鎵(GaN)被認為是第三代極具發展潛力的半導體材料之ㄧ，其薄膜基板在製作白、藍光發光二極體上扮演著關鍵性的角色，而氮化鎵奈米線可作為生物DNA的感測器…等，由此可見此材料在半導體領域上應用的重要性，故掌握其基本的力學性質將有助於應用及技術方面的突破。
本文主要利用分子動力學透過奈米壓痕及奈米彎曲的方法，探討氮化鎵二維薄膜及一維奈米線結構之機械性質，分析不同模擬參數的條件下，材料本身力學性質的變化。模擬結果發現，在不同溫度下不同維度之氮化鎵材料之楊氏係數、硬度均隨著溫度的上升而下降，且薄膜與奈米線之間在力學數值結果上存在著差異性，並且發現(100)方向奈米線之楊氏係數及硬度會高於(110)方向。針對(100)方向之氮化鎵奈米線進行奈米彎曲測試，結果顯示不同的壓入深度可以明顯的區別出奈米線的彈塑性行為，而在高溫狀態下奈米線受彎曲作用後，其斷裂面呈現較佳的延性，其降伏強度與剛性則隨著溫度的升高而下降。

Molecular Dynamics is one of methodology to study the mechanical properties of nanostructure. Molecular Dynamics simulation consists of the predicted and modified steps and obeys the classical Newton’s equation of motion. GaN was regard as one of the most potential semiconductor material of third generation. The GaN films play an important role in white or blue LED fabrication, and GaN nanowires are widely used in the fields of biomedical sensor devices. Investigating of their mechanical properties is the key to improve techniques and applications in the future.
This paper investigates the mechanical properties of GaN films and nanowires under nanoindentaion and nanobending by using Molecular Dynamics (MD) in different simulation parameters. The results show that the Young’s modulus and hardness of GaN films and nanowires decrease with the temperature increase. Besides, the GaN films are distinguished from nanowires in numerical results. The Young’s modulus and hardness of (100) oriented GaN nanowire is higher than (110). Furthermore, this paper also discuss the deformation process of (100) oriented GaN nanowire under nanobending test. The elastic-plastic deformation can be recognized clearly in different indentation depths. The ductility of (100) oriented GaN nanowires at higher temperature is better than lower temperature, and the yielding strength and stiffness decrease with temperature increase.

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