The effect of a stacking fault on the electronic properties of dopants in gallium arsenide

We performed a theoretical investigation on the effects of extended defects on the structural and electronic properties of dopant atoms in gallium ars enide. We observed that silicon impurities segregate at GaAs stacking fault s. A Si atom at a Ga site in a stacking fault in either a neutral or a nega tively charged state is energetically favourable as compared to a Si atom a t a Ga site in a crystalline environment by as much as 0.2 eV. Additionally , a substitutional Si impurity in the negative charge state in a stacking f ault has a distinct structure as compared to the same impurity in a crystal . The results suggest that the stacking fault may prevent the formation of metastable defects, such as DX centres.