Effect of nitrogen-induced modification of the conduction band structure on electron transport in GaAsN alloys

We report pressure studies of conductivity, photoconductivity and Hall effe ct in Si doped GaAs0.986N0.014. We observed that pressure causes an unusual ly large reduction of the electron mobility in this compound (factor of 2.5 in the pressure range 0 to 2 GPa). We also measured the pressure coefficie nt of the energy gap and we found it, in agreement with previous reports, t o be reduced by almost 40% compared to that of GaAs. These results can be s uccessfully explained by a recently proposed, phenomenological model based on the concept of an anticrossing interaction between localized N-related s tates (resonant with the conduction band) and conduction band states. This model explains well the reduction of the pressure coefficient of the bandga p and predicts an enhancement of the effective mass of GaAs1-xNx. The decre ase of electron mobility observed in the present study is in agreement with this latter prediction.