Smart Advanced Materials/Devices by Laser/Plasma Process

为了获得高质量的薄膜和器件，本课题研究了利用KrF准分子激光器和YAG激光器进行脉冲激光沉积(PLD)技术。为了了解PLD过程中不同沉积条件下薄膜的生长机理，还研究了激光等离子体的动力学。提出了等离子体离子注入和介质阻挡放电相结合的PLD新工艺。在碳基材料的制备中，介绍了激光诱导荧光法(LIF)，结果表明，C2和C3在碳靶附近存在，而在远离靶心的轴外区域存在。碳基C、C_2和C_3对类金刚石碳膜的光学性质起主导作用。在场效应管、磁传感器、发光器件和非挥发性存储器件中制备了由超导薄膜Y-Ba-Cu-O、铁电材料Pb-Zr-Ti-O、巨磁阻性La-Sr-Mn-O、光子型氧化锌等氧化物薄膜组成的异质结，在无气氛(50mTorr)气氛中制备的CNX薄膜的N/C比为1.0。铁电材料PbZTiO/超导Y-BaCuO/YSZ涂层硅衬底具有良好的铁电性能，其剩余极化(Pr)为20μC/cm2，矫顽场(EC)为40 kV/cm，La-Sr-Mn-O/MgO在室温下的电阻率峰值温度为330K，磁阻为15%(H=0.7T)。Au/Pb-Zr-Ti/La-Sr-Mn-O/MgO电容器的Pr为22μC/cm~2，EC为27KV/cm。PLD提供了高质量的氧化锌薄膜。沉积的薄膜有(002)、(003)个X射线衍射峰，对应的c轴长度为0.529 nm。本文开发的PLD工艺是一种很有前途的沉积21世纪材料的技术，旨在制备纳米结构，如纳米颗粒、纳米晶体和纳米颗粒嵌入器件。

In this research program, development of pulsed laser deposition (PLD) using KrF excimer laser and YAG laser has been studied to obtain high-quality thin films and devices. Dynamics of laser produced plasmas was also investigated to understand the growth mechanism of thin films at various deposition conditions in PLD process. We proposed the new PLD process combined with plasma ion implantation and dielectric barrier discharge. In carbon based material preparation, laser induced fluorescence (LIF) method was introduced and showed that C_2 and C_3 exist near the carbon target and off-axis area far the target center. Carbon radicals C, C_2, and C_3 dominate optical property of the diamondlike carbon films. Heterostructures consisting of oxide thin films such as superconducting Y-Ba-Cu-O, ferroelectrics Pb-Zr-Ti-O, colossal magnetoresistivity La-Sr-Mn-O, photonics ZnO have been prepared for field effect transistor, magnetic sensor, light emitting device, and nonvolatile memory device.The CNx thin films deposited in NO ambient gas (50mTorr) showed N/C ratio of 1.0. The ferroelectric Pb-Zr-Ti-O/superconducting Y-Ba-Cu-O/YSZ coated Si substrate heterostructure had the good ferroelectric properties of the remanent polarization (Pr) of 20 μC/cm^2 and the coercive field (Ec) of 40 kV/cm.The La-Sr-Mn-O/MgO showed resistivity peak temperature of 330K and the magnetoresistance of 15% (H=0.7T) at room temperature. The Au/Pb-Zr-Ti/La-Sr-Mn-O/MgO capacitor had Pr of 22 μC/cm^2 and Ec of 27kV/cm. The PLD provides high quality ZnO thin films. The deposited films shows (002), (003) XRD peaks corresponding to c-axis length of 0.529nm. The PLD process developed here is a promising technique to deposit 21 century materials aiming for nanostructures such as nanoparticles, nanocrystals and nanoparticles embedded devices.