Publication Date:
2014-07-15
Description:
Ultrafast pump-probe transient reflectance (TR) spectroscopy was used to study carrier dynamics in an epitaxial perovskite oxide thin film of LaFeO 3 (LFO) with a thickness of 40 unit cells (16 nm) grown by molecular beam epitaxy on (LaAlO 3 ) 0.3 (Sr 2 AlTaO 6 ) 0.7 (LSAT). TR spectroscopy shows two negative transients in reflectance with local maxima at ∼2.5 eV and ∼3.5 eV which correspond to two optical transitions in LFO as determined by ellipsometry. The kinetics at these transients were best fit with an exponential decay model with fast (5–40 ps), medium (∼200 ps), and slow (∼ 3 ns) components that we attribute mainly to recombination of photoexcited carriers. Moreover, these reflectance transients did not completely decay within the observable time window, indicating that ∼10% of photoexcited carriers exist for at least 3 ns. This work illustrates that TR spectroscopy can be performed on thin (
Print ISSN:
0003-6951
Electronic ISSN:
1077-3118
Topics:
Physics
