First-principles study on absolute band edge positions for II–VI semiconductors at (1 1 0) surface

Using the first-principles method, the absolute band edge positions were calculated for the (1 1 0) surface of zinc-blende type II–VI semiconductors. The thickness of the slab which was used to model the (1 1 0) surface has significant effect on the band edge positions. The variation trend of Eg with the slab thickness is dominated by that of ECBM, while almost irrespective of EVBM. This phenomenon can be interpreted by the electron (at CBM) and hole (at VBM) effective masses. The absolute band edge alignments with different slab thickness can give reasonable interpretation for a series of photocatalytic experiments.