title: BaTiO3 integration with nanostructured epitaxial (100), (110), and (111) germanium for multifunctional devices.
abstract: Ferroelectric-germanium heterostructures have a strong potential for multifunctional devices. Germanium (Ge) is attractive due to its higher electron and hole mobilities while ferroelectric BaTiO3 is promising due to its high relative permittivity, which can make next-generation low-voltage and low-leakage metal-oxide semiconductor field-effect transistors. Here, we investigate the growth, structural, chemical, and band alignment properties of pulsed laser deposited BaTiO3 on epitaxial (100)Ge, (110)Ge, and (111)Ge layers. Cross-sectional transmission electron microscopy micrographs show the amorphous nature of the BaTiO3 layer and also show a sharp heterointerface between BaTiO3 and Ge. The appearance of strong Pendellösung oscillation fringes from high-resolution X-ray diffraction implies the presence of parallel and sharp heterointerfaces. The valence band offset relation of ΔEV(100) ≥ ΔEV(111) > ΔEV(110) and the conduction band offset relation of ΔE(C)(110) > ΔE(C)(111) ≥ ΔE(C)(100) on crystallographically oriented Ge offer significant advancement for designing new-generation ferroelectric-germanium-based multifunctional devices.
authors.affiliation: Advanced Devices & Sustainable Energy Laboratory (ADSEL), Bradley Department of Electrical and Computer Engineering, ‡Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech , Blacksburg, Virginia 24061, United States.
authors.forename: Mantu K
authors.initials: MK
authors.lastname: Hudait
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Nikhil
authors.initials: N
authors.lastname: Jain
authors.forename: Deepam
authors.initials: D
authors.lastname: Maurya
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Ron
authors.initials: R
authors.lastname: Varghese
authors.forename: Shashank
authors.initials: S
authors.lastname: Priya
mesh_terms: D017609:Barium Compounds / Q000737:chemistry*; D003460:Crystallization; D005857:Germanium / Q000737:chemistry*; D007834:Lasers; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology; D012666:Semiconductors; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D017609:Barium Compounds; D005857:Germanium; C024547:barium titanate(IV); D014025:Titanium