类金刚石薄膜由于其独特的物理化学特性,使得该薄膜在光学、电学、机械、医学、航空航天等领域得到了广泛应用。等离子体增强化学气相沉积(plasma enhanced chemical vapor deposition,PECVD)制备类金刚石是近几十年兴起的新的制备类金...类金刚石薄膜由于其独特的物理化学特性,使得该薄膜在光学、电学、机械、医学、航空航天等领域得到了广泛应用。等离子体增强化学气相沉积(plasma enhanced chemical vapor deposition,PECVD)制备类金刚石是近几十年兴起的新的制备类金刚石薄膜的方法,因其对沉积温度要求低,对基底友好,同时还具有沉积速率快和无转移生长的优势,获得了越来越多的研究者关注。详细介绍了类金刚石薄膜优异的特性,阐述了在等离子化学气相沉积条件下,不同沉积条件对沉积类金刚石薄膜结构特性的影响。衬底的选择直接影响着沉积类金刚石薄膜的性能,不同的衬底直接决定着生成类金刚石结构中sp^(3)相的数量和质量;沉积参数是最为常见的控制条件,对沉积薄膜的总体效果影响也是最大的,改变沉积参数,沉积薄膜的表面将会变得更加光滑致密;常用的掺杂元素是硅和氮,掺杂元素的引入往往是为了降低沉积薄膜的内应力,提高与衬底间的结合力,延长使用寿命等;由于很难直接在金属上沉积类金刚石薄膜,所以常通过制备复合层来改善沉积效果。最后对类金刚石薄膜的发展以及今后研究方向进行了展望。展开更多
Titanium dioxide is coated on the surface of MCM-41 wafer through the plasma enhanced chemical vapor deposition （PECVD） method using titanium isopropoxide （TTIP） as a precursor. Annealing temperature is a key fact...Titanium dioxide is coated on the surface of MCM-41 wafer through the plasma enhanced chemical vapor deposition （PECVD） method using titanium isopropoxide （TTIP） as a precursor. Annealing temperature is a key factor affecting crystal phase of titanium dioxide. It will transform an amorphous structure to a polycrystalline structure by increasing temperature. The optimum anatase phase of TiO2 which can acquire the best methanol conversion under UV-light irradiation is obtained under an annealing temperature of 700℃ for 2 h, substrate tem- perature of 500~C, 70 mL. min1 of oxygen flow rate, and 100W of plasma power. In addition, the films are composed of an anatase-rutile mixed phase, and the ratio of anatase to rutile varies with substrate temperature and oxygen flow rate. The particle sizes of titanium dioxide are between 30.3 nm and 59.9nm by the calculation of Scherrer equation. Under the reaction conditions of ll6.8mg.L-1 methanol, 2.9mg.L-1 moisture, and 75~C of reaction temperature, the best conversion of methanol with UV-light is 48.2% by using the anatase-rutile （91.3/ 8.7） mixed phase TiO2 in a batch reactor for 60 min. While under fluorescent light irradiation, the best photoactivity appears by using the anatase-rutile （55.4/44.6） mixed phase TiO2 with a conversion of 40.0%.展开更多
文摘类金刚石薄膜由于其独特的物理化学特性,使得该薄膜在光学、电学、机械、医学、航空航天等领域得到了广泛应用。等离子体增强化学气相沉积(plasma enhanced chemical vapor deposition,PECVD)制备类金刚石是近几十年兴起的新的制备类金刚石薄膜的方法,因其对沉积温度要求低,对基底友好,同时还具有沉积速率快和无转移生长的优势,获得了越来越多的研究者关注。详细介绍了类金刚石薄膜优异的特性,阐述了在等离子化学气相沉积条件下,不同沉积条件对沉积类金刚石薄膜结构特性的影响。衬底的选择直接影响着沉积类金刚石薄膜的性能,不同的衬底直接决定着生成类金刚石结构中sp^(3)相的数量和质量;沉积参数是最为常见的控制条件,对沉积薄膜的总体效果影响也是最大的,改变沉积参数,沉积薄膜的表面将会变得更加光滑致密;常用的掺杂元素是硅和氮,掺杂元素的引入往往是为了降低沉积薄膜的内应力,提高与衬底间的结合力,延长使用寿命等;由于很难直接在金属上沉积类金刚石薄膜,所以常通过制备复合层来改善沉积效果。最后对类金刚石薄膜的发展以及今后研究方向进行了展望。
文摘Titanium dioxide is coated on the surface of MCM-41 wafer through the plasma enhanced chemical vapor deposition （PECVD） method using titanium isopropoxide （TTIP） as a precursor. Annealing temperature is a key factor affecting crystal phase of titanium dioxide. It will transform an amorphous structure to a polycrystalline structure by increasing temperature. The optimum anatase phase of TiO2 which can acquire the best methanol conversion under UV-light irradiation is obtained under an annealing temperature of 700℃ for 2 h, substrate tem- perature of 500~C, 70 mL. min1 of oxygen flow rate, and 100W of plasma power. In addition, the films are composed of an anatase-rutile mixed phase, and the ratio of anatase to rutile varies with substrate temperature and oxygen flow rate. The particle sizes of titanium dioxide are between 30.3 nm and 59.9nm by the calculation of Scherrer equation. Under the reaction conditions of ll6.8mg.L-1 methanol, 2.9mg.L-1 moisture, and 75~C of reaction temperature, the best conversion of methanol with UV-light is 48.2% by using the anatase-rutile （91.3/ 8.7） mixed phase TiO2 in a batch reactor for 60 min. While under fluorescent light irradiation, the best photoactivity appears by using the anatase-rutile （55.4/44.6） mixed phase TiO2 with a conversion of 40.0%.
