Electron transport in heterostructure hot-electron diodes

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Abstract
Vertical electron transport in GaAs/AlxGa1−xAs heterostructures is investigated through Monte Carlo simulations of the heterostructure hot‐electron diode (HHED). A fully self‐consistent ensemble Monte Carlo algorithm with a realistic numerical band structure is employed. Results show that transport in the HHED is dominated by the influence of the heterointerface closest to the emitting contact. Two distinct modes of conduction are observed. One is a low‐conductivity regime where transport is predominantly by gamma valley tunneling. The other is a high‐conductivity regime where transport is mainly due to thermionic emission of electrons from the GaAs to the AlxGa1−xAs. In the latter most of the electrons are in the L and X valleys when they transfer to the wide‐gap material. In these valleys the propagation from GaAs to AlxGa1−xAs is virtually unimpeded as the band‐edge discontinuities are small in contrast to the situation for gamma electrons.