We have investigated the effects of N on the electronic properties of Si-doped Ga As1-x Nx alloy films and AlGaAsGaAsN modulation-doped heterostructures. For bulk-like alloy films, the electron mobility is independent of free carrier concentration and arsenic species, and decreases with increasing N composition. Thus, N-related defects are the main source of scattering in the dilute nitride alloys. For AlGaAsGaAsN heterostructures, gated and illuminated magnetoresistance measurements reveal a two-dimensional electron gas mobility which increases with carrier concentration to a constant value. Thus, in contrast to the long-range ionized scattering sources which are dominant in N-free heterostructures, N-induced neutral scattering sources are the dominant source of scattering in AlGaAsGaAsN heterostructures. Finally, a decrease in free carrier concentration with increasing N composition is apparent for bulk-like films, while the free carrier concentration is independent of N composition in modulation-doped heterostructures. Since N and Si atoms are spatially separated in the modulation-doped heterostructures, N-Si defect complexes in the bulk GaAsN layers are likely acting as trapping centers.
ASJC Scopus subject areas
- Physics and Astronomy(all)