Using a first-principles method, an investigation was made of the structural and electronic properties of grain boundaries in polycrystalline CdTe and the effects of co-passivation of elements with very distinct electronegativities. Of the 2 types of grain boundaries studied here, it was found that the Cd core was less harmful to carrier transport, but was difficult to passivate with impurities such as Cl and Cu, whereas the Te core created a high defect density below the conduction band minimum. However, all of these levels could be removed by co-passivation of Cl and Cu. The analysis indicated that, for most polycrystalline systems, co-passivation or multi-passivation was required in order to passivate the grain boundaries.

Effect of Copassivation of Cl and Cu on CdTe Grain Boundaries. L.Zhang, J.L.F.Da Silva, J.Li, Y.Yan, T.A.Gessert, S.Wei: Physical Review Letters, 2008, 101[15], 155501