KTa_(0.77)Nb_(0.23)O_3纳米片的微结构和Raman光谱研究

Study on the microstructure and Raman scattering of KTa_(0.77)Nb_(0.23)O_3 nanoplates

以Ta2O5,Nb2O5和KOH为原料,采用水热法合成边缘尺寸约100nm,厚约10nm的KTa0.77Nb0.23O3(KTN)单晶纳米片.X线衍射(XRD)结果表明,产物为立方相钙钛矿结构;X线荧光光谱(XRF)显示,纳米片中K、Ta和Nb的比例约为1∶0.70∶0.22,与KTa0.77Nb0.23O3化学计量比有轻微的偏移,这主要是KTN纳米片表面Ta元素强烈的自吸收引起的.室温拉曼光谱研究显示纳米片有8个声子振动峰,频率分别位于166,214,274,462,562,765,876和1 098cm-1,较之块体散射峰发生了红移和较大的展宽,这可能是由于纳米片的表面应力或结构缺陷导致,如堆垛层错等.

KTa0.77Nb0.23O3（KTN） single crystalline nanoplates with edge sizes of about 100 nm and thickness of about 10 nm had been synthesized by hydrothermal method using Ta2O5,Nb2O5 and KOH served as raw materials.X-ray diffraction（XRD） result showed that the samples had perovskite structure with cubic phase;X-ray fluorescence（XRF） spectrum exhibited that the resulting nanoplates contain ing K,Ta and Nb cations in a 1∶0.70∶0.22 ratio,which was deviating from the stoichiometry of KTa0.77Nb0.23O3 slightly,which might be due to the strong self-absorption of Ta element in the surface of KTN nanoplates.Room temperature Raman spectrum of nanoplates revealed seven phonon vibration peaks,which located at 166、214、274、462、562、765、876 and 1 098 cm-1,respectively.The scattering profile was to be more diffused and enlarged comparing to that of bulk materials.This might be induced by the surface stress or structure defects,such as stacking faults.