Details

Autor(en) / Beteiligte

• Kananen, B. E.
• Halliburton, L. E.
• Scherrer, E. M.
• Stevens, K. T.
• Foundos, G. K.
• Chang, K. B.
• Giles, N. C.

Titel

Electron paramagnetic resonance study of neutral Mg acceptors in β-Ga2O3 crystals

Ist Teil von

• Applied physics letters, 2017-08, Vol.111 (7)

Ort / Verlag

Melville: American Institute of Physics

Erscheinungsjahr

2017

Quelle

AIP Journals

Beschreibungen/Notizen

• Electron paramagnetic resonance (EPR) is used to directly observe and characterize neutral Mg acceptors ( M g Ga 0 ) in a β-Ga2O3 crystal. These acceptors, best considered as small polarons, are produced when the Mg-doped crystal is irradiated at or near 77 K with x rays. During the irradiation, neutral acceptors are formed when holes are trapped at singly ionized Mg acceptors ( M g Ga − ). Unintentionally present Fe3+ (3d5) and Cr3+ (3d3) transition-metal ions serve as the corresponding electron traps. The hole is localized in a nonbonding p orbital on a threefold-coordinated oxygen ion adjacent to an Mg ion at a sixfold-coordinated Ga site. These M g Ga 0 acceptors (S = 1/2) have a slightly anisotropic g matrix (principal values are 2.0038, 2.0153, and 2.0371). There is also partially resolved 69Ga and 71Ga hyperfine structure resulting from unequal interactions with the two Ga ions adjacent to the hole. With the magnetic field along the a direction, hyperfine parameters are 2.61 and 1.18 mT for the 69Ga nuclei at the two inequivalent neighboring Ga sites. The M g Ga 0 acceptors thermally convert back to their nonparamagnetic M g Ga − charge state when the temperature of the crystal is raised above approximately 250 K.