Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1676602 | Thin Solid Films | 2006 | 6 Pages |
Abstract
We have performed a picosecond ultrasonic study of the effects of oxygen partial pressure on the acoustic velocity in zirconium oxide films made by radio frequency reactive sputtering. To derive more accurate and reliable values of sound velocity, various reflective layers were used to enhance the echo signals of acoustic pulses photoexcited by an ultrafast laser. It is found that the acoustic responses of the samples with a W reflective layer are much stronger than those with a Si or SiO2 reflective layer. In addition, the W reflective layer generates extra photoacoustic waves, which can be utilized to improve the accuracy of velocity measurement. The thin film velocities we measured were 10â¼24% less than the bulk value, and exhibited a strong dependence on the growth conditions and the microstructure of films.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
Ta-Ching Li, Nen-Wen Pu, Ben-Je Lwo, Long-Jang Hu, Chin-Hsing Kao,