Abstract
Temperature-dependent Hall-effect measurements are performed on cubic GaN layers grown by plasma-assisted molecular-beam epitaxy on (100) GaAs substrates. We find that under N-rich conditions, cubic GaN films are -type with hole concentrations of ≈ and mobilities of about 350 /V s at room temperature. The acceptors have an activation energy of eV. Ga-rich growth conditions result in -type conductivity with electron concentrations of about and room-temperature mobilities of /Vs. Since for -type samples a strong influence of the underlaying semi-insulating GaAs substrate is observed, a two-layer model is used to evaluate the Hall data, yielding a shallow donor with an activation energy of eV and a deeper donor with eV.
- Received 17 July 1996
DOI:https://doi.org/10.1103/PhysRevB.54.R11118
©1996 American Physical Society