论文标题
纳米法规薄膜的密度随厚度而变化
Density of Nanometrically Thin Amorphous Films Varies by Thickness
论文作者
论文摘要
自然界中的生物可以改变无定形前体相的短距离顺序，从而控制所得的晶体结构。这种现象启发了对所选材料无定形阶段中短程顺序修饰的效果的研究。发现通过原子层沉积法沉积的氧化铝的无定形薄膜在结构上随着大小而变化。正如原子模拟所预测的，并且还证实了较薄的薄膜，显示了更多的4个协调氧化铝地点。这些原子的改变有望改变无定形薄膜平均密度。密度确实随氧化铝层的厚度而变化，并且测得的效应甚至比理论上的预测更强。通过沉积过程来解释这种效果，其中每个新沉积的层都是一个新的表面层，它记得其结构，从而导致薄膜的密度较低。
Organisms in nature can alter the short-range order of an amorphous precursor phase, thereby controlling the resulting crystalline structure. This phenomenon inspired an investigation of the effect of modifying the short-range order within the amorphous phase of a selected material. Amorphous thin films of aluminum oxide deposited by the atomic layer deposition method were found to vary structurally as a function of size. Thinner films, as predicted and also confirmed by atomistic simulations, exhibited more 4 coordinated alumina sites. These atomistic alterations were expected to change the amorphous thin film average density. The density indeed varied with the alumina layer thickness, and the measured effect was even stronger than predicted theoretically. This effect is explained in terms of the deposition process, where each newly deposited layer is a new surface layer that remembers its structure, resulting in thin films of substantially lower density.
