Transient current study of low‐temperature grown GaAs using an n‐i‐n structure

The electrical properties of molecular beam epitaxy (MBE) grown low‐temperature GaAs (LT‐GaAs) by current transient spectroscopy (CTS) has been investigated. At least three deep traps have been observed in LT‐GaAs grown at 250 °C and annealed at 600 °C. The deepest level is dominant and has an activation energy of 0.82 eV, which is the same as that of the midgap donor, EL2. This is consistent with the activation energy of resistivity of this sample (0.77 eV), which is close to that for bulk nondoped semi‐insulating wafers. These results indicate that the Fermi level of annealed LT‐GaAs grown at 250 °C is pinned by the deep level at the midgap that is generally ascribed to AsGa antisite defects.