Scientists at the University of Minnesota have developed a new method for creating thin films of perovskite oxide semiconductors, a class of “smart” materials that can change in response to stimuli such as light, magnetic fields, or electric fields.
This discovery will allow researchers to use these properties and even combine them with other emerging nanoscale materials to create better devices, such as sensors, smart textiles, and flexible electronics.
The team developed a new way to create a membrane of strontium titanate, a metal oxide, using a technique called hybrid molecular beam epitaxy. This method allows them to create a freestanding membrane of virtually any oxide material, exfoliate it, and then transfer it onto any subject of interest. This opens up the possibility of combining these materials with other nanoscale materials to create highly functional and efficient devices.
One of the major challenges in making freestanding membranes of oxide materials is that the atoms are bonded in three dimensions, unlike in two-dimensional materials like graphene. The team overcame this challenge by using titanium that was already bonded to oxygen, which allowed for automatic stoichiometric control and prevented the oxygen in the material from oxidizing the graphene.
This new method has the potential to revolutionize the synthesis of complex oxide materials and enable the creation of a wide range of functional devices. “We have a way to make these complex oxide membranes with an automatic stoichiometric control. No one has been able to do that,” said Bharat Jalan, a professor at the University of Minnesota and senior author of the study.
The paper is published in Science Advances, a journal published by the American Association for the Advancement of Science (AAAS).