Crystallite growth limits in amorphous oxides
Crystallite growth limits in amorphous oxides
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DOI：
10.1088/1361-6382/ad14b7
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发表时间：
2023-12
影响因子：
3.5
通讯作者：
S. Linker;Christopher Ausbeck;R. DeSalvo;V. Granata;Brecken Larsen;Tugdual LeBohec;Yangyang Liu;Akilah Miller;M. Mondin;Joshua Neilson;H. Themann
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文献类型：
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作者：
S. Linker;Christopher Ausbeck;R. DeSalvo;V. Granata;Brecken Larsen;Tugdual LeBohec;Yangyang Liu;Akilah Miller;M. Mondin;Joshua Neilson;H. Themann
非晶薄膜沉积后的热退火处理改善了介质镜的光学性能。然而，过高的温度会导致结晶，导致机械和光学性能的劣化。因此，退火被限制在“低于”结晶阈值的温度。阈值由X射线衍射（XRD）测量确定，其需要大量的结晶材料用于检测，但已经表明，在低于阈值温度的其他非晶涂层中可能存在微晶群。在这项研究中，XRD测量显示在退火过程中在非晶氧化物涂层内生长到有限和可预测的尺寸的微晶，该尺寸基于晶体和周围非晶相之间的密度差和平均材料的杨氏模量。这些微晶可能是点状的，非常弱的散射体显示在LIGO测试质量时，离轴成像。
Post deposition thermal annealing of amorphous coatings improves optical properties of dielectric mirrors. However, excessive temperatures cause crystallization, resulting in a degradation of mechanical and optical properties. Therefore, annealing is limited to temperatures ‘below’ the crystallization threshold. The threshold is determined by x-ray diffraction (XRD) measurement which requires a significant amount of crystallized material for detection, yet it has been shown that a population of crystallites may exist in otherwise amorphous coatings below the threshold temperature. In this study XRD measurements show crystallites that grow during annealing within amorphous oxide coatings to a limited and predictable size predicated on the difference in density between the crystal and the surrounding amorphous phase and the average material’s Young’s modulus. These crystallites may be the point-like, extremely weak scatterers revealed in the LIGO test masses when imaged off-axis.