Experimental evidence for spin–triplet states in Titanium implanted AlN film: An electron spin resonance study

Spin carrying defects in wide-bandgap semiconductors are promising candidates for the development of quantum information and quantum sensing technology. Here we report experimental evidence for the formation of paramagnetic defects in AlN films, subjected to high-energy hydrogen and titanium ion implantation. X-ray diffraction and Raman spectroscopy show that ion species and implantation process could alter the amount of local strain in AlN films. Electron spin resonance spectroscopy reveals resonance peaks with g-value higher than the one of a free electron (2.0023) for both H-implanted and Ti-implanted AlN films. The origin of these peaks is identified and attributed to different types of point defects. For the Ti-implanted film, in addition to the central peak, a half-field resonance peak has been detected and assigned to spin–triplet (S=1). These results provide new insight into the electronic spin state of point defects in AlN, which opens up interesting perspectives for applications to quantum devices.