摘要
用Sol Gel法制备KTN多晶粉末,在富氧气氛下烧结富钾KTN陶瓷,代替KTN单晶作为靶材,用PLD技术结合后期退火技术,在透明石英单晶(100)上制备出高取向的透明KTN薄膜,对薄膜厚度、折射率、伏～安(I～V)特性、介电特性进行了测试与分析.I～V特性表明,低电场强度下,I～V服从欧姆定律,高电场强度下,I～V服从平方关系,可用空间电荷限制电流模型解释.电容～测试电场频率(C～F)特性表明,低频电容色散大,高频色散小,10kHz时介电常数为12600.
Using the Sol-Gel method for producing the KTN ultrafine powder and the sintering technique with K2O atmosphere to prepare KTN ceramics as the targets instead of the KTN single crystal, highly oriented KTN thin films were produced on the transparent single crystal quartz （ 100 ） by the pulsed laser deposition （ PLD ）. The XRD analysis indicates that the perovskite structure with （h00） orientation is the major phase （ 〉98% ） in KTN. The Current-Voltage characteristics were found to be Ohmic at low fields and space-charge-limited at higher fields. This phenomenon is reasonably explained by SCLC theory. The leakage current was lower than 250 p.A/mm^2 at 0 - 5 V, which shows the film has good ferroelectric performances. The frequency dependence of dielectric constant results demonstrates that the dispersion of electric capacity is large at low frequency but small at high frequency. The dielectric constant was 12600 at frequency of 10 kHz. The P -E hysteresis loop shows that the remanent polarization and the coercive field are 9.25 μC/cm^2 and 7.32 kV/cm, respectively. The SEM results shows that the surfaces are homogeneous, smooth, crack-free and dense. The refractive index was 1. 776 at incident wave length 1.2μm, the thickness 968 nm, and the growth rate 0. 027 nm per pulse.
关键词
PLD
KTN
薄膜
石英单晶
PLD, KTN, Thin film, Single crystal quartz
作者简介
Email： wxd@ mail. tsinghua, edu. cn
