Growth of strongly textured FeCO 3FeCO₃ thin films for application in research of nuclear quantum optics with ultrashort-pulsed laser deposition

Growth of strongly textured FeCO 3FeCO₃ thin films on substrates was achieved with ultrashort-pulsed laser deposition using 810-nm, 46-fs ablation pulses. The crystallinity and composition were verified with X-ray diffraction and Raman spectroscopy. Using Mössbauer spectroscopy, it is shown that the deposited FeCO 3FeCO₃ thin films possess the film quality required for application in research of nuclear quantum optics. It is found that a relatively low substrate temperature is crucial for growing a strongly textured film of FeCO₃FeCO₃ while avoiding decomposition of FeCO₃FeCO₃ into Fe₂O ₃Fe₂O₃ and CO₂CO₂. This supports the importance of the use of ultrashort-pulsed laser deposition in providing adatoms with high mobility for attaining good crystallinity. The surface morphology was characterized by surface profilometry, scanning electron microscopy and atomic force microscopy. It is found to be significantly affected by changing the ablation laser parameters, including laser fluence, pulse duration, and on-target spot size. The results show that the peak deposition flux must be below approximately 0.03 nm/pulse in order to grow a flat film.