Additional phonon modes and close satellite valleys crucial for electron transport in hexagonal gallium nitride

Brazis, R.; Raguotis, R.
July 2004
Applied Physics Letters;7/26/2004, Vol. 85 Issue 4, p609
Academic Journal
Conventional models of electron transport in hexagonal GaN crystals predicting electron drift velocity peak value up to 3.2×107 cm/s at 140–220 kV/cm and a pronounced negative differential mobility at higher fields are revised. The new model is suggested accounting for the additional low-energy optical phonon modes (∼26 meV) and the satellite valley location close (400 meV) to the conduction band bottom. Electron scattering on these and conventional (∼92 meV) LO-phonon modes together with the fast intervalley exchange is shown to limit electron drift velocity (<1.9×107 cm/s at T=300 K), in excellent agreement with the time-of-flight experiment.


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