利用光声技术研究SrTiO3薄膜的热扩散率

Study on Thermal Diffusivity of SrTiO_3 Thin Film by Photoacoustic Technique

利用背激发检测光声技术测量了8个不同厚度SrTiO3薄膜的热扩散率,研究光声信号的幅值、相位及薄膜热扩散率随膜厚的变化规律发现,随着薄膜厚度的增大,光声信号的幅值和相位均逐渐减小;薄膜的热扩散率随着厚度的增加先增大后减小,在一定厚度下,热扩散率达到最大。厚度不变时,光声信号幅值、相位及薄膜热扩散率与入射光调制频率的相关性研究表明,光声信号幅值与相位随频率的增大呈非线性减小,但薄膜热扩散率的测量值在不同的调制频率下较稳定。

The thermal diffusivity rates of 8 different thickness SrTiO3 films are measured based on the back ex- citation photoacoustic technology,the variety of photoacoustic signal amplitude,phase and the thermal diffusion rate with the film thickness is studied. It is found that the photoacoustic signal amplitude and phase gradually decrease with the increase of film thickness,while the thermal diffusion rate of the thin film increases first, then decreases, and in a certain thickness,the thermal diffusion rate reaches its maximum. On the condition of the same thickness, the research on the relativity between the photoacoustic signal amplitude, phase, film thermal diffusivity rate and the modulation frequency shows that the photoacoustic signal amplitude and phase non-linearly decrease with the in- crease of frequency,but the thermal diffusivity rates of the thin film are stable in different modulation frequency.