Theory of steady-state high-field hole transport in GaSb and AlxGa1−xSb: The impact ionization resonance

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Abstract
Calculations of the steady‐state impact ionization rate of holes in GaSb and AlGaSb are presented based on a Monte Carlo simulation with the unique inclusion of a complete band structure (derived using the K*P method) and quantum effects such as initial state collision broadening. It is determined, by comparisons to existing experimental data, that the holes in the split‐off band play the most important role in impact ionization in both GaSb and GaAlSb. The experimental data are fit quite well at low applied electric fields where the recently discovered resonance in the hole impact ionization rate occurs. It is found that the resonance data can be explained, using the parametrized Keldysh formula, if the impact ionization threshold energy in both the heavy‐ and light‐hole bands is ∼1.40 eV, roughly twice the band‐gap energy, The threshold energy in the split‐off bands is taken to be equal to the split‐off energy for Δ>