MANILA, Philippines (Apr 25) – Scientists at the University of the Philippines Diliman College of Science (UPD-CS) are exploring a new way to create thin films using a different kind of laser technology, challenging traditional methods. Their research focuses on understanding the complexities of using a low-energy femtosecond pulsed laser deposition (fs-PLD) process.
Typically, creating thin films involves powerful lasers with longer pulses. Inspired to innovate, researchers from the UPD-CS Materials Science and Engineering Program (MSEP) and the UPD-CS National Institute of Physics (NIP) experimented with a lower-energy femtosecond laser that fires much shorter pulses.
The team, including Joy Kristelle De Mata and Dr. Lean Dasallas from MSEP, and Dr. Roland Sarmago and Dr. Wilson Garcia from NIP, specifically studied how thin films of BSCCO (bismuth strontium calcium copper oxide) form. BSCCO is a high-temperature superconductor used in various applications like power cables and magnets.
A key hurdle in this process is making sure the film has the exact same mix of elements as the original material. Any imbalance can significantly change how the material behaves. De Mata explained, “A key challenge in this process is maintaining the stoichiometric ratio of elements in the film, as deviations can significantly impact material properties.” To get a clearer picture, the scientists looked at how different types and pressures of background gas affected the film’s makeup and how evenly the material spread during deposition.
Their findings showed that using low-energy fs-PLD with high gas pressure resulted in a film composition that did not perfectly match the original material. Existing computer models commonly used to predict material spread in this process also failed to accurately explain these discrepancies. This suggests that the fs-PLD method is more intricate than first thought, pointing to a need for better models to improve how thin films are made for practical uses.
De Mata added, “Our results demonstrate that the background gas type and pressure significantly influence film composition.” While fs-PLD has some advantages over the older nanosecond laser method (ns-PLD), getting the right element mix in thin films remains tough. She stressed the need for more work to fine-tune the deposition conditions.
Looking at industrial uses, De Mata noted that while fs-PLD looks promising, it is not quite ready for large-scale manufacturing in areas like electronics. Issues include inconsistencies in the film’s element mix compared to the original material, which could pose problems in mass production. Also, because fs-PLD uses less energy, the process is slower, potentially increasing costs for making large quantities.
“Despite these challenges, fs-PLD remains a valuable technique for high-quality thin film fabrication in research and specialized applications,” she stated. The team plans to explore other factors next, like heating the surface where the film is deposited, to see how temperature affects the process. De Mata highlighted that current models do not fully account for the differences they observed in film composition and that they aim to improve these models for better use with fs-PLD. The facts matter, and this Philippine research pushes the boundaries of material science.
