Band structures of molecular beam epitaxially grown MoSe₂–WSe₂ heterobilayers with different stacking orders on SrTiO₃(111) substrate

Using SrTiO3(111) as a substrate, we grew WSe2/MoSe2 and MoSe2/WSe2 heterobilayers (HBLs) by molecular beam epitaxy. The in situ scanning-tunneling microscopic measurements revealed that different stacking orders on SrTiO3(111) can result in different interlayer distances dMo–W with dMo–W = 0.77 nm in WSe2/MoSe2/SrTiO3(111) and dMo–W = 0.66 nm in MoSe2/WSe2/SrTiO3(111) separately. A combined study of angle-resolved photoemission spectroscopic measurements and first-principles calculations further demonstrates that the interlayer distance can essentially affect the band structures of MoSe2–WSe2 HBLs. Our work shows that MoSe2/WSe2 and WSe2/MoSe2 HBLs on SrTiO3(111) substrate would be a platform for studying the properties of transition metal dichalcogenides HBLs, and the modulation of interlayer distance by changing the stacking order of a HBL on a substrate would be a freedom to engineer the electronic structures.