Quasi-zero lattice mismatch and band alignment of BaTiO3 on epitaxial (110)Ge
Growth, structural, and band alignment properties of pulsed laser deposited amorphous BaTiO3 on epitaxial molecular beam epitaxy grown (110) Ge layer, as well as their utilization in low power transistor are reported. High-resolution x-ray diffraction demonstrated quasi-zero lattice mismatch of BaTiO3 on (110) Ge. Cross-sectional transmission electron microscopy micrograph confirms the amorphous nature of BaTiO3 layer as well as shows a sharp heterointerface between BaTiO3 and Ge with no traceable interfacial layer. The valence band offset, Delta E-v, of 1.99 +/- 0.05 eV at the BaTiO3/(110) Ge heterointerface is measured using x-ray photoelectron spectroscopy. The conduction band offset, Delta E-c, of 1.14 +/- 0.1 eV is calculated using the bandgap energies of BaTiO3 of 3.8 eV and Ge of 0.67 eV. These band offset parameters for carrier confinement and the interface chemical properties of the BaTiO3/(110) Ge system are significant advancement towards designing Ge-based p-and n-channel metal-oxide semiconductor field-effect transistors for low-power application. (C) 2013 AIP Publishing LLC.