Ab initio calculation of intrinsic point defects in CuInSe2

Preliminary ab initio calculation of different point defects energy and electronic density of states have been performed on the prototype chalcopyrite semiconductor CuInSe₂. The simulation method used is based on the density functional theory within the framework of pseudo-potentials and plane waves basis. The isolated neutral defects considered are: V_Cu, V_In, V_Se, Cu_i, In_i, In_Cu, Cu_In and the complex defects are 2Cu_i+Cu_In, In_Cu+Cu_In and 2V_Cu+In_Cu, some of which being computed for the first time by advanced ab initio techniques. In agreement with previous results, we show that some point defects (such as V_Cu) and pair defects (2V_Cu+In_Cu) have very low formation energies. Some energies of formation were found significantly lower than previous estimations. The comparison of the formation energies with the exchange correlation (LDA or GGA) is discussed. The perturbation induced by the presence of some of these ideal defects on the density of states is also presented.