本征晶格缺陷对BNT铁电薄膜光响应性能的影响

摘要

用溶胶-凝胶法在YSZ/Si衬底上制备Bi3．15 Nd0．85 Ti3 O12（BNT）铁电薄膜，研究了退火气氛和退火温度对BNT薄膜的光响应性能的影响。对不同退火气氛和退火温度下的BNT薄膜进行微观结构和光响应性能表征。研究结果表明：随着退火气氛中氧含量的降低，光响应增大，BNT薄膜中氧空位起到了为光生载流子传输提供通道的作用；随着退火温度的降低，光开启电压和饱和光电导增大，BNT薄膜中高密度的晶界虽然阻碍了光生载流子的迁移，却有利于使光生载流子在晶界处及时分开。%The Bi3.15 Nd0.85 Ti3 O12 (BNT)ferroelectric thin film was fabricated on the YSZ/Si substrate using a sol-gel process,and the effects of annealing atmosphere and annealing temperature on the photoresponse of BNT thin films were investigated.The mi-crostructure and photoresponse of the BNT film were characterized.The results suggest that the photoresponse increases with the decreasing oxygen concentration in the atmosphere,which indicates that oxygen vacancies in BNT films provide a path for photo-generated carriers transportation.The threshold voltage of photoconduction,as well as the saturation photoconduction increases with the decreasing annealing temperature.Though grain boundaries hinder the migration of carriers,they promote the separation of photogenerated carriers timely.