Band alignment between (100)Si and complex rare earth∕transition metal oxides

The electron energy band alignment between (100)Si and several complex transition∕rare earth (RE) metal oxides (⁠$LaScO3$⁠, $GdScO3$⁠, $DyScO3$⁠, and $LaAlO3$⁠, all in amorphous form) is determined using a combination of internal photoemission and photoconductivity measurements. The band gap width is nearly the same in all the oxides $(5.6–5.7eV)$ yielding the conduction and valence band offsets at the Si∕oxide interface of $2.0±0.1$ and $2.5±0.1eV$⁠, respectively. However, band-tail states are observed and these are associated with Jahn-Teller relaxation of transition metal and RE cations which splits their $d*$ states.