Nitrogen Related Deep Levels in GaAsN Films Investigated by a Temperature Dependence of Piezoelectric Photothermal Signal

The temperature dependences of the piezoelectric photo-thermal (PPT) signals from unintentionally doped p-type GaAsN films grown on semi-insulating GaAs substrate were measured from 80 to 300 K. From the theoretical analysis based on the rate equation for the recombination of photo exited carriers to the localized levels, we identified five majority hole traps, P1-P5 in GaAsN films. Among them, estimated concentrations of the P3 and P5 traps increased with the nitrogen contents. Therefore, we concluded that these two traps were due to nitrogen-related recombination centers in GaAsN.