The spin relaxation of nitrogen donors in 6H SiC crystals as studied by the electron spin echo method

Journal Article · Thu Apr 07 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4945438· OSTI ID:22594573

Shanina, B.; Kalabukhova, E. ^[1]; Pöppl, A. ^[2]; Lančok, J. ^[3]; Mokhov, E. ^[4]

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1. V.E. Lashkaryov Institute of Semiconductor Physics, NASU, Kyiv 03028 (Ukraine)
2. Institute of Experimental Physics II, Leipzig University, Leipzig D-04103 (Germany)
3. Institute of Physics of the Czech Academy of Sciences, Prague 182 21 (Czech Republic)
4. A.F. Ioffe Physical Technical Institute, RAS, St. Petersburg 194021 (Russian Federation)

We present the detailed study of the spin kinetics of the nitrogen (N) donor electrons in 6H SiC wafers grown by the Lely method and by the sublimation “sandwich method” (SSM) with a donor concentration of about 10{sup 17 }cm{sup −3} at T = 10–40 K. The donor electrons of the N donors substituting quasi-cubic “k1” and “k2” sites (N{sub k1,k2}) in both types of the samples revealed the similar temperature dependence of the spin-lattice relaxation rate (T{sub 1}{sup −1}), which was described by the direct one-phonon and two-phonon processes induced by the acoustic phonons proportional to T and to T{sup 9}, respectively. The character of the temperature dependence of the T{sub 1}{sup −1} for the donor electrons of N substituting hexagonal (“h”) site (N{sub h}) in both types of 6H SiC samples indicates that the donor electrons relax through the fast-relaxing centers by means of the cross-relaxation process. The observed enhancement of the phase memory relaxation rate (T{sub m}{sup −1}) with the temperature increase for the N{sub h} donors in both types of the samples, as well as for the N{sub k1,k2} donors in Lely grown 6H SiC, was explained by the growth of the free electron concentration with the temperature increase and their exchange scattering at the N donor centers. The observed significant shortening of the phase memory relaxation time T{sub m} for the N{sub k1,k2} donors in the SSM grown sample with the temperature lowering is caused by hopping motion of the electrons between the occupied and unoccupied states of the N donors at N{sub h} and N{sub k1,k2} sites. The impact of the N donor pairs, triads, distant donor pairs formed in n-type 6H SiC wafers on the spin relaxation times was discussed.

• OSTI ID: 22594573
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 13; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACOUSTIC ESR
CONCENTRATION RATIO
CRYSTALS
ELECTRONS
HYDROGEN 6
KINETICS
NITROGEN
PHONONS
RELAXATION TIME
SCATTERING
SILICON
SILICON CARBIDES
SPIN
SPIN-LATTICE RELAXATION
SUBLIMATION
TEMPERATURE DEPENDENCE