Interface engineering of Ge using thulium oxide: Band line-up study

- Thulium oxide layers on germanium were investigated.
- The valence band offset was found to be 2.95 eV.
- The band gap of thulium oxide was found to be 5.3 eV from the Tauc method.
- A sub-band gap absorption at 3.2 eV points to a bulk thulium oxide defect.
- A permittivity of 14 was derived from electrical measurements.