Band-structure engineering to control impact ionisation and related high-field processes

Alloying with even small amounts of highly mismatched atoms can have dramatic and beneficial effects on the electronic band structure of semiconductors. For example, dilute amounts of nitrogen in GaAsN or GaInAsN may cause considerable disruption of the conduction band while leaving the valence band relatively unaltered. This means that the impact ionisation rate of electrons can be made much smaller than the rate for holes leading, for example, to the production of low-noise avalanche photodiodes.