On the effect of oxygen on the creation of colour centres in swift heavy ion-irradiated AlN

We readdress the nature and creation mechanism of the defects absorbing at 4.7 eV in Swift Heavy Ion (SHI)-irradiated AlN semiconductor. Irradiations are performed in different controlled atmospheres (vacuum, oxygen, helium or argon partial pressure) to investigate the coupled effects of (i) the synergy between electronic excitations (Se) and nuclear collisions (Sn) for point defect creation and (ii) SHI-induced impurity introduction/diffusion into the AlN layer. We found that the synergy, previously reported, between Se and Sn for defect formation must also be related to the presence of oxygen during irradiation. At the same Se, the synergy parameter is indeed increased by up to two orders of magnitude during irradiation under O2 compared to irradiation under vacuum. By SHI irradiation and by a fine-tuning of the irradiation atmosphere, we then control the activation or inhibition of these light-emitted point defects (oxygen-vacancy complexes) which can be used as qubits for applications in quantum computing.