Effect of dangling bonds of ultra-thin silicon film surface on electronic states of internal atoms

► Dangling bonds at surfaces of one or both sides of film were directly treated. ► The impacts on the electronic states of the internal atoms were estimated. ► Electronic states appeared in the midgap by removing terminated H at surfaces. ► The concentration at 18th layer in a 36-layer model is estimated at 1.2 × 1014 cm−3. ► This concentration is not so low and may affect device performances.