单晶钨纳米片/带的气相合成及其力学性能

摘要

The morphology, microstructure and elemental composition of the single-crystal W nanosheetsanobelts synthesized by chemical vapor deposition, using WO2(OH)2 and H2 as reaction precursor, were characterized by SEM, TEM and EDS. The as-synthesized W nanosheetsanobelts have a length of 10~60μm and a thickness of 100~300 nm. The thermodynamics (surface energy minimization) and kinetics (competition growth) of crystal growth are found to be the decisive roles on the well-defined geometrical shape and two-dimensional growth of the W nanosheetsanobelts, and a growth model for the as-synthesized W nanosheetsanobelts is also proposed. The nanoindentation results show that the W nanosheets on Si(100) substrate exhibit a hardness of 6.3 GPa and an elastic modulus of 176 GPa. The effects of the surface oxide, the substrate effect, and the non-ideal contact between substrate and nanosheets of the measurement results are discussed.%采用气态WO2(OH)2和H2作为反应气氛，通过化学气相沉积合成厚度100~300 nm、边长10~60μm的单晶W纳米片/带，通过SEM、TEM和EDS等测试分析手段对产物的形貌、结构和元素成分进行系统表征。结果表明：晶体生长热力学(表面能最小)和动力学(竞争生长)条件分别在单晶W纳米片/带的规则几何外形和二维生长方式中起到决定性作用，据此提出了单晶W纳米片/带的生长模型。纳米压痕仪测试结果表明，Si(100)基底上W纳米片的硬度和弹性模量分别为6.3 GPa和176 GPa。分别从表面氧化层，基底与纳米片之间非理想接触和基底效应等3个方面对测试结果进行了分析和讨论。