Electron traps in thin layers of low-temperature-grown gallium arsenide with As-Sb nanoclusters

Abstract

Electron traps in low-temperature-grown ∼40-nm-thick GaAs layers containing nanometer As-Sb clusters have been studied using deep-level transient spectroscopy. Measurements at various bias voltages and small-amplitude filling pulses have allowed the identification of two groups (T1 and T2) of traps with substantially different thermal electron emission rates. It is shown that the density of traps T2 (with an activation energy of 0.56 ± 0.04 eV and electron capture cross section of 2 × 10⁻¹³−10⁻¹²cm²) is ∼2 × 10¹²cm₋₂, while the density of traps T1 (0.44 ± 0.02 eV and 2 × 10⁻¹⁴−10⁻¹³ cm², respectively) is ten times lower. It is assumed that, according to the existence of the two cluster groups observed in the layers under study, traps T2 are associated with clusters 4–7 nm in diameter and traps T1, with clusters up to ∼20 nm in diameter.