Effects of heavy-ion and light-ion irradiation on the room temperature carrier dynamics of InGaAs/GaAs quantum wells

The effects of irradiation by Ni-9(+), Ne-20(+), He+ and H-1(+) ions on the carrier dynamics of InGaAs/GaAs quantum well heterostructures were studied using a femtosecond time-resolved up-conversion photoluminescence method. The carrier capture time for the light ions He+ and H+ was found to be almost independent of the irradiation dose, while for the irradiation with heavy ions Ni+ and Ne+ it decreases with the dose. The most efficient carrier collection into the quantum wells was observed for the Ne+-irradiated sample, with a shortest capture time of about 1 ps. The heavy-ion-irradiated samples exhibited the shortest decay times (lifetime of carriers), which were 0.54 ps for Ne+ and 0.62 ps for Ni+. Irradiation by light ions He+ and H+ was as effective as with the heavy ions in achieving the desired short lifetimes, but for similar nuclear energy deposition and penetration depth for each ion species in the sample, much higher ion doses needed to be applied for lighter ions than did Ne+ or Ni+ to yield the same carrier lifetime. When comparing the results of irradiation for the Ne+-irradiated sample with those of the Ni+-irradiated one, we conclude that although the carrier lifetime and ion doses were about the same for both the methods, the Ne-20(+) ions are preferred over Ni-59(+) due to the faster carrier capture dynamics and remarkably lower implantation energy (0.4 MeV versus 10 MeV) needed to obtain the desired irradiation induced effects.