Kuo Chi-Liang, Huang Michael H
Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
Nanotechnology. 2008 Apr 16;19(15):155604. doi: 10.1088/0957-4484/19/15/155604. Epub 2008 Mar 11.
We report the growth of ultralong β-Ga(2)O(3) nanowires and nanobelts on silicon substrates using a vapor phase transport method. The growth was carried out in a tube furnace, with gallium metal serving as the gallium source. The nanowires and nanobelts can grow to lengths of hundreds of nanometers and even millimeters. Their full lengths have been captured by both scanning electron microscope (SEM) and optical images. X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images have been used to study the crystal structures of these nanowires and nanobelts. Strong blue emission from these ultralong nanostructures can be readily observed by irradiation with an ultraviolet (UV) lamp. Diffuse reflectance spectroscopy measurements gave a band gap of 4.56 eV for these nanostructures. The blue emission shows a band maximum at 470 nm. Interestingly, by annealing the silicon substrates in an oxygen atmosphere to form a thick SiO(2) film, and growing Ga(2)O(3) nanowires over the sputtered gold patterned regions, horizontal Ga(2)O(3) nanowire growth in the non-gold-coated regions can be observed. These horizontal nanowires can grow to as long as over 10 µm in length. Their composition has been confirmed by TEM characterization. This represents one of the first examples of direct horizontal growth of oxide nanowires on substrates.
我们报道了采用气相传输法在硅衬底上生长超长β-Ga₂O₃纳米线和纳米带的情况。生长过程在管式炉中进行，使用金属镓作为镓源。纳米线和纳米带可以生长到数百纳米甚至毫米的长度。它们的全长已通过扫描电子显微镜（SEM）和光学图像捕获。X射线衍射（XRD）图谱和透射电子显微镜（TEM）图像已用于研究这些纳米线和纳米带的晶体结构。用紫外（UV）灯照射时，可以很容易地观察到这些超长纳米结构发出强烈的蓝光。漫反射光谱测量给出这些纳米结构的带隙为4.56 eV。蓝光发射在470 nm处显示出一个带最大值。有趣的是，通过在氧气气氛中对硅衬底进行退火以形成厚SiO₂膜，并在溅射的金图案化区域上生长Ga₂O₃纳米线，可以观察到在未涂金区域中水平生长的Ga₂O₃纳米线。这些水平纳米线可以生长到长达10 µm以上的长度。它们的组成已通过TEM表征得到证实。这代表了氧化物纳米线在衬底上直接水平生长的首批实例之一。
