Production of multicharged iron ions and application to enhancement of photo-catalytic performance invisible light region on TiO_2 thin films

在2.45 GHz电子回旋共振(ECR)离子源(泰科装置)中利用固体材料产生多电荷铁离子，并在拱形ECR等离子体中通过反应溅射获得大面积的二氧化钛薄膜。产生铁离子的方法是直接溅射和欧姆加热，即随铁丝蒸发。蒸发的中性铁原子在ECR等离子体中被电离。将多电荷离子从靠近蒸发器的镜面反面引出，形成多电荷离子束。在不同的实验条件下，研究了提取离子电流的电荷态分布。试图通过改进微波和离子束引取器的发射来进一步提高离子束的大小。我们已经成功地产生了高达Fe^&lt；10+&gt；的多电荷离子。在氮化硼(BN)坩埚的情况下，氮气被释放到1500℃以上。然后产生多电荷的氮离子，并将其应用于材料加工。我们通常在Si(100)衬底上形成约100 nm的二氧化钛薄膜。我们用X射线衍射法表征了二氧化钛的结晶度，用蒸馏水的接触角来评价其光催化性能。二氧化钛薄膜为锐钛矿型和金红石型。为了提高纳米二氧化钛薄膜在可见光区域的光催化性能，在硅衬底上分别注入了Fe^&lt；3+&gt；和N^&lt；3+&gt；离子。光催化效率在2×10~(-1)cm~(-2)~(-2)时达到最大。在植入前后，用荧光灯照射4h，比较蒸馏水在二氧化钛表面的接触角。掺杂后的二氧化钛薄膜在可见光区域的光催化性能好于注入前，在紫外光区域没有恶化。

Multicharged iron ions have been produced from solid materials in a 2.45GHz electron cyclotron resonance (ECR) ion source (TAIKO device), and also large area TiO_2 thin films are individually produced by reactive sputtering in an arched ECR plasma.Production of Fe ions has been made by direct sputtering, and by Ohmic heating, i.e., evaporating with Fe filament. The vaporized neutral Fe atoms are ionized in the ECR plasma. The multicharged ions are extracted from the opposite side of mirror end against the evaporator, and then multicharged ion beam is formed. The charge-state distributions (CSD) of the extracted ion current are investigated in various experimental conditions. Magnitude of ion beams has been tried to further enhance by improving the launch of the microwave and the extractor of ion beams. We have succeeded in producing multicharged ions up to Fe^<10+>. In the case of boron nitride (BN) crucible, nitrogen gas is released above 1500℃. And then multicharged nitrogen ions also produced and can be applied to material processing.We normally form the TiO_2 thin film (〜100nm) on the Si(100) substrates. We measure the x-ray diffraction for characterization of the TiO_2 crystallinity and the contact angle of distilled water for estimation of photo-catalytic performance. The crystalline TiO_2 thin films are anatase and rutile phases. Fe^<3+> and N^<3+> ions were implanted into TiO_2 thin films on the Si substrates in order to enhance photo-catalytic performance in visible light region. The maximum efficiency of photo-catalytic performance has been obtained at the dose of about 2X10^<15> cm^<-2>. We compared contact angles of distilled water on the TiO_2 by illuminating fluorescent light for four hours before and after implantation. Photo-catalytic performance of the TiO_2 thin film in visible light region after implantation is better than that before implantation without deterioration in ultraviolet light region.