Small non-uniform basal crystal fields in HVPE free-standing GaN:Mg as evidenced by angular dependent and frequency-dependent EPR

Abstract

We studied thin-film and free-standing Mg-doped GaN using multi-frequency electron paramagnetic resonance (EPR) at 3–3.5 K and 9.4–130 GHz. Free-standing samples exhibit a highly anisotropic intensity, varying by a factor of 20 from 0° to 60°. In contrast, the intensity of the thin-film samples is significantly more isotropic, varying by no more than 10% over the same range of angles. The angular dependent intensity can be modeled in both free-standing and thin-film samples similarly to the g-factor anisotropy reported for thin films, supporting the theoretical predictions that the hole is on a basal site around the Mg acceptor. In addition, frequency-dependent transmission EPR measurements reveal a distribution of in free-standing samples, indicating that the local basal crystal field is non-uniform.

Terahertz electron paramagnetic resonance generalized spectroscopic ellipsometry: The magnetic response of the nitrogen defect in 4H-SiC

“…2 The possibility to access electron spin dynamics at much higher, i.e., Terahertz (THz) frequencies is attractive. Large energies permit better understanding of spin dynamics in single-molecule magnets, for example, 3,4 and allow investigation of systems with large zero-field splitting such as in transition metal complexes, 5,6 or in ultrawide-bandgap semiconductors, e.g., SiC [7][8][9] and group-III nitrides 10,11 for quantum technologies, or the recently emerging monoclinic gallium oxide for high voltage electronic applications. [12][13][14][15][16][17][18][19] To bring spin resonances into the THz range, superconducting magnets reaching large magnetic fields are necessary.…”

Dynamics Studies of Nitrogen Interstitial in GaN from Ab Initio Calculations

“…With deep levels transient spectroscopy (DLTS), Kanegae et.al [ 9 ] observed that E 3 ( E c −0.60 eV) and H 1 ( E v +0.87 eV) are dominating traps in n-type GaN, and they attributed H 1 trap to the gallium vacancy or C related defects. Sunay et.al [ 10 ] applied electron paramagnetic resonance (EPR) to find that the hole is around the Mg acceptor. In addition, by using positron annihilation spectroscopy (PAS), EPR, and density functional theory (DFT), Bardeleben et.al [ 11 ] found that the isolated N interstitial is unstable and prefers to form a split interstitial configuration, which is located at E c −1.0 eV.…”

Terahertz electron paramagnetic resonance generalized spectroscopic ellipsometry: The magnetic response of the nitrogen defect in 4H-SiC

“…2 The possibility to access electron spin dynamics at much higher, i.e., Terahertz (THz) frequencies is attractive. Large energies permit better understanding of spin dynamics in single-molecule magnets, for example, 3,4 and allow investigation of systems with large zero-field splitting such as in transition metal complexes, 5,6 or in ultrawide-bandgap semiconductors, e.g., SiC 7-9 and group-III nitrides 10,11 for quantum technologies, or the recently emerging monoclinic gallium oxide for high voltage electronic applications. [12][13][14][15][16][17][18][19] To bring spin resonances into the THz range, superconducting magnets reaching large magnetic fields are necessary.…”