Evidence of N substitution by Mn in GaN

Abstract

We report on the lattice location of Mn in wurtzite GaN using β − emission channeling. In addition to the majority substituting for Ga, we locate up to 20% of the Mn atoms in N sites. We propose that the incorporation of Mn in N sites is enabled under sufficiently high concentrations of N vacancies, and stabilized by a highly charged state of the Mn cations. Since N substitution by Mn impurities in wurtzite GaN has never been observed experimentally or even considered theoretically before, it challenges the current paradigm of transition metal incorporation in wide-gap dilute magnetic semiconductors.

Direct observation of the lattice sites of implanted manganese in silicon

“…The lattice sites of 56 Mn were inferred from the angular dependence of the emission yield of its β − particles along various axial and planar directions. [17][18][19][20] As it turns out, even at low concentrations only a minority of Mn (< 30%) occupies in fact ideal substitutional sites, while the large majority forms more complex structures with implantation defects or p-type dopants. Our results not only clearly illustrate the difficulties in using ion implantation as means of substitutional Mn doping, but also shed light on the general interaction of Mn with defects and impurities in Si.…”

Emission channeling studies on transition-metal doped GaN and ZnO: Cation versus anion substitution

“…[15][16][17][18]). However, using the emission channeling (EC) technique, we have recently located significant fractions of implanted Mn impurities in N (anion) sites in GaN [19]. Similarly, we have also reported the minority anion (O) substitution by Co and Mn impurities in ZnO [20].…”

“…Here, we present the β − emission channeling experiments on 61 Co-implanted GaN. We discuss these results in the context of our recent reports of minority anion substitution in Mn-implanted GaN [19] and Mn/Co-implanted ZnO Pereira et al (2011) [20], particularly in terms of the advantages of the emission channeling technique in such cases of multi-site occupancy. …”

“…We report β − emission channeling experiments on implanted Co in GaN and, together with our previous reports on implanted Co in ZnO [20] as well as Fe and Mn in GaN and ZnO [19][20][21][22], we discuss the technique's advantages in such cases of multi-site occupancy.…”

“…The canonical example is Mn-doped GaAs, where Mn can occupy both Ga-substitutional and tetrahedral interstitial sites [2,3]. Whereas substitutional Mn provides both the localized magnetic moment and the itinerant hole that mediates the magnetic coupling, interstitial Mn acts as a compensating defect, both electrically and magnetically [4].…”