Ga/N flux ratio influence on Mn incorporation, surface morphology, and lattice polarity during radio frequency molecular beam epitaxy of (Ga,Mn)N

Abstract

The effect of the Ga/N flux ratio on the Mn incorporation, surface morphology, and lattice polarity during growth by rf molecular beam epitaxy of (Ga,Mn)N at a sample temperature of 550 °C is presented. Three regimes of growth, N-rich, metal-rich, and Ga-rich, are clearly distinguished by reflection high-energy electron diffraction and atomic force microscopy. Using energy dispersive x-ray spectroscopy, it is found that Mn incorporation occurs only for N-rich and metal-rich conditions. For these conditions, although x-ray diffraction in third order does not reveal any significant peak splitting or broadening, Rutherford backscattering clearly shows that Mn is not only incorporated but also substitutional on the Ga sites. Hence, we conclude that a MnxGa1−xN alloy is formed (in this case x∼5%), but there is no observable change in the c-axis lattice constant. We also find that the surface morphology is dramatically improved when growth is just slightly metal rich. When growth is highly metal-rich, but not Ga-rich, we find that Ga polarity flips to N polarity. It is concluded that the optimal growth of Ga-polar MnGaN by rf N-plasma molecular beam epitaxy occurs in the slightly metal-rich regime.

The effects of implanted nitrogen ions on the magnetic properties of Mn-implanted GaN

“…a decrease of N-vacancies. Mn impurities in GaN diffused through N-vacancies [11,12]. Thus, the Mn diffusion could be suppressed in the (Mn+N)-implanted sample, preventing Mn atoms from accumulating to form such precipitates, leading to a reduction in the amount of antiferromagnetic Mn-N binary phases, Mn 3N2 and Mn6N2.58 (Fig.…”

Co‐implantation of Mn + N into p‐type GaN for high T C ferromagnetism

“…This means that N vacancies, which play a critical role in weakening the ferromagnetic property in (Ga, Mn)N films due to the compensation effect, decreased with the coimplantation. It was reported that the diffusion of dopant atoms in GaN films decreases with the reduction of the concentration of N vacancies [8]. Thus, the diffusion of Mn atoms could be suppressed in such an N-rich condition, preventing Mn atoms from accumulating in the precipitates.…”

Dependence of the magnetic properties of MnGaN epitaxial layers on external electrical field

“…These results are connected with the spin of the electrons belonging to 3d orbital of the Mn atom, which can be considered to be a precondition for magnetic properties of Mn x Ga 1-x N. It is expected that these properties would have a possible application in spintronics and hence it determines the scientific efforts for investigation of the impact of Mn atom, which substitutes on Ga site in the structure of Mn x Ga 1-x N [4][5][6][7][8]. A Field effect device based on change of the magnetic properties of layers of Mn x Ga 1-x N due to application of external voltage is the subject of consideration in this paper.…”