Defect energy levels in p-type GaAsBi and GaAs grown by MBE at low temperatures

This is the authors' abstract. We don't add key points for this paper.

Deep level defects in p-type GaAs 1− x Bi x ( x < 1%) and GaAs grown by molecular beam epitaxy at substrate temperatures of 330 °C and 370 °C have been characterized by deep level transient spectroscopy. We find that incorporating Bi into GaAs at 330 °C does not affect the total concentration of hole traps, which is ∼4 × 10 16 cm −3 , comparable to the concentration of electron traps observed in Si-doped GaAsBi having a similar alloy composition. Increasing the growth temperature of the p-type GaAsBi ( x = 0.8%) layer from 330 °C to 370 °C reduces the hole trap concentration by an order of magnitude. Moreover, the defects having near mid-gap energy levels that are the most efficient non-radiative recombination centers are present only in GaAsBi layers grown at the lower temperature. These new results are discussed in the context of previous measurements of n-type GaAs and GaAsBi layers grown under similar conditions.