Molecular beam epitaxy of BaSi2 thin films on Si(001) substrates

► BaSi2 layers were grown epitaxially on Si(001), despite the large lattice mismatch. ► a-Axis-oriented BaSi2 layers were grown. ► The grain size of BaSi2 on Si(001) was found to be as large as 1 μm. ► The grain size of BaSi2 on Si(001) is much larger than that on Si(111).