Theoretical study of (112) GBs and stacking faults in polycrystalline CuInSe2 thin films

Using first-principle electronic structure theory, we have investigated the interface energy and electronic structure of (112) GBs and stack faults in chalcopyrite CuInSe₂. Our calculations show that both (112) GB and stack fault have small interface energies and tend to be Cu-poor. Including Cu-vacancy brings a shallow energy level close to valence band maximum, and results in a narrowed bandgap. This will be beneficial to the performance of CuInSe₂ thin film solar cells.