Hu Po-Sheng, Wu Cheng-En, Chen Guan-Lin
Institute of Photonic System, National Chiao Tung University, Tainan City 71150, Taiwan.
Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan City 71150, Taiwan.
Materials (Basel). 2017 Dec 21;11(1):3. doi: 10.3390/ma11010003.
In this research, the Zn(C₅H₇O₂)₂·xH₂O-based growth of ZnO micro/nanostructures in a low temperature, vapor-trapped chemical vapor deposition system was attempted to optimize structural and optical properties for potential biomedical applications. By trapping in-flow gas molecules and Zinc vapor inside a chamber tube by partially obstructing a chamber outlet, a high pressure condition can be achieved, and this experimental setup has the advantages of ease of synthesis, being a low temperature process, and cost effectiveness. Empirically, the growth process proceeded under a chamber condition of an atmospheric pressure of 730 torr, a controlled volume flow rate of input gas, N₂/O₂, of 500/500 Standard Cubic Centimeters per Minute (SCCM), and a designated oven temperature of 500 °C. Specifically, the dependence of structural and optical properties of the structures on growth duration and spatially dependent temperature were investigated utilizing scanning electron microscopy, X-ray diffraction (XRD), photoluminescence (PL), and ultraviolet-visible transmission spectroscopy. The experimental results indicate that the grown thin film observed with hexagonal structures and higher structural uniformity enables more prominent structural and optical signatures. XRD spectra present the dominant peaks along crystal planes of (002) and (101) as the main direction of crystallization. In addition, while the structures excited with laser wavelength of 325 nm emit a signature radiation around 380 nm, an ultraviolet lamp with a wavelength of 254 nm revealed distinctive photoluminescence peaks at 363.96 nm and 403.52 nm, elucidating different degrees of structural correlation as functions of growth duration and the spatial gradient of temperature. Transmittance spectra of the structures illustrate typical variation in the wavelength range of 200 nm to 400 nm, and its structural correlation is less significant when compared with PL.
在本研究中，尝试在低温、气相捕获化学气相沉积系统中基于Zn(C₅H₇O₂)₂·xH₂O生长ZnO微纳结构，以优化其结构和光学性能，用于潜在的生物医学应用。通过部分阻塞腔室出口来捕获腔室管内的流入气体分子和锌蒸气，可以实现高压条件，并且这种实验装置具有易于合成、低温工艺和成本效益高的优点。根据经验，生长过程在腔室条件下进行，大气压为730托，输入气体N₂/O₂的控制体积流量为500/500标准立方厘米每分钟（SCCM），指定的炉温为500°C。具体而言，利用扫描电子显微镜、X射线衍射（XRD）、光致发光（PL）和紫外可见透射光谱研究了结构的结构和光学性能对生长持续时间和空间相关温度的依赖性。实验结果表明，观察到的具有六边形结构和更高结构均匀性的生长薄膜具有更突出的结构和光学特征。XRD光谱显示沿(002)和(101)晶面的主峰为结晶的主要方向。此外，当用325nm激光波长激发时，结构发射出约380nm的特征辐射，但波长为254nm的紫外灯在363.96nm和403.52nm处显示出独特的光致发光峰，阐明了作为生长持续时间和温度空间梯度函数的不同程度的结构相关性。结构的透射光谱说明了200nm至400nm波长范围内的典型变化，并且与PL相比，其结构相关性不太显著。
