Researchers present new method for fabricating thin films of perovskite oxide semiconductors

Jan 4, 2023 05:00 PM ET
  • Researchers from the University of Minnesota Twin Cities-led, University of Wisconsin-- Madison and Pacific Northwest National Laboratory have actually developed a new method for making thin films of perovskite oxide semiconductors, a class of "smart" materials with distinct properties that can transform in response to stimuli like light, magnetic fields, or electrical fields.
Researchers present new method for fabricating thin films of perovskite oxide semiconductors

Their work might enable scientists to harness these properties and also even integrate them with various other arising nano-scale materials to make better tools such as sensors, smart textiles, as well as flexible electronics.

Producing materials in thin-film kind makes them easier to incorporate right into smaller components for electronic devices. Numerous thin films are used a technique called epitaxy, which consists of placing atoms of a material on a substrate, or a design template of sorts, to develop a thin sheet of material, one atomic layer each time. Nonetheless, most thin films produced through epitaxy are "stuck" on their host substrate, limiting their uses. If the thin film is detached from the substrate to end up being a freestanding membrane, it becomes much more functional.

The University of Minnesota-led group has located a new way to efficiently produce a membrane of a particular metal oxide-- strontium titanate-- as well as their method circumvents a number of issues that have actually burdened the synthesis of free standing metal oxide films in the past.

" We have produced a procedure where we can make a free standing membrane of basically any type of oxide material, exfoliate it, and after that transfer it onto any kind of topic of passion we desire," stated Bharat Jalan, an elderly author on the paper and also a teacher and also Covering Chair in the University of Minnesota Department of Chemical Engineering and also Materials Science. "Currently, we can benefit from the functionality of these materials by combining them with other nano-scale materials, which would enable a vast array of extremely functional, highly efficient devices."

Making free standing membranes of "smart" oxide materials is challenging due to the fact that the atoms are bonded in all 3 dimensions, unlike in a two-dimensional material, such as graphene. One method of making membranes in oxide materials is making use of a technique called remote epitaxy, which makes use of a layer of graphene as an intermediary in between the substrate and the thin-film material.

This approach permits the thin-film oxide material to create a thin film and also be peeled, like a piece of tape, from the substrate, creating a free standing membrane. Nonetheless, the greatest barrier to utilizing this method with metal oxides is that the oxygen in the material oxidizes the graphene on call, messing up the example.

Utilizing hybrid molecular beam epitaxy, a technique pioneered by Jalan's lab at the University of Minnesota, the researchers had the ability to navigate this issue by using titanium that was already bonded to oxygen. Plus, their method permits automatic stoichiometric control, indicating they can immediately control the composition.

" We revealed for the very first time, as well as conclusively by doing a number of experiments, that we have a new method which permits us to make complex oxide while making sure that graphene is not oxidized. That's a significant landmark in synthesis science," Jalan claimed. "As well as, we now have a way to make these intricate oxide membranes with an automatic stoichiometric control. No person has actually been able to do that."

" These intricate oxides are a broad class of materials that have a lot of actually essential innate features to them," claimed Koester, also a senior author of the research study and also the supervisor of the Minnesota Nano Facility at the University of Minnesota Twin Cities. "Currently, we can think of using them to make very small transistors for electronic tools, as well as in a wide selection of various other applications consisting of flexible sensors, smart textiles, and non-volatile memories."

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