X-ray diffraction studies of the growth of vanadium dioxide nanoparticles
X-ray diffraction studies of the growth of vanadium dioxide nanoparticles
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DOI：
10.1063/1.2786917
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发表时间：
2007-10
影响因子：
3.2
通讯作者：
S. Pauli;R. Herger;P. Willmott;E. U. Donev;J. Suh;R. Haglund
中科院分区：
文献类型：
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作者：
S. Pauli;R. Herger;P. Willmott;E. U. Donev;J. Suh;R. Haglund
我们首次利用五圆x射线衍射仪原位表征了脉冲激光沉积制备的二氧化钒纳米颗粒薄膜的生长，以便提供薄膜生长过程中的结构信息。在脉冲N2O反应气源存在下烧蚀钒金属靶，并在Si（001）和Al2O3（0001）衬底上生长薄膜。光学测量证实，以这种方式沉积的薄膜在大约70°C时表现出众所周知的VO2金属-绝缘体转变。室温下在硅衬底上生长的VO2薄膜是非晶态的，非常光滑。这些在热退火后变得相当粗糙，因为VO2相以半球形岛的形式结晶出来。这些薄膜在最初的几层单层中也含有微量的V2O5纳米颗粒相，尽管纳米颗粒中VO2的结晶度相当高。相比之下，在蓝宝石衬底上生长的VO2纳米颗粒处于最佳状态。
We have characterized for the first time in situ the growth of vanadium dioxide nanoparticulate films prepared by pulsed-laser deposition, using a five-circle x-ray diffractometer, in order to provide structural information as the films are grown. A vanadium metal target was ablated in the presence of a pulsed N2O reactive gas source, and films were grown on Si(001) and Al2O3(0001) substrates. Optical measurements confirmed that the films deposited in this way exhibit the well-known VO2 metal–insulator transition at approximately 70 °C. The VO2 films grown at room temperature on silicon substrates are amorphous and extremely smooth. These become considerably rougher upon thermal annealing, as the VO2 phase crystallizes out in the form of hemispherical islands. These films also contain traces of a V2O5 nanoparticle phase in the first few monolayers, although the degree of VO2 crystallinity in the nanoparticles is quite high. In contrast, the VO2 nanoparticles grown on the sapphire substrates are in the for...