Alexandr A. Ezhevskii *, Andrey V. Soukhorukov *, Davud V. Guseinov *, Sergey A. Popkov *, Anatoliy V. Gusev †, Vladimir A. Gavva † 1 Department of Physics, Lobachevsky State University, Nizhniy Novgorod, Russia † Department of Semiconductor Materials, Institute of Chemistry of High Purity Substances RAS, Nizhniy Novgorod, Russia Isotopic Effects in Spin Resonance of Electrons with Different Localization in Silicon

Electron Spin Resonance for spin system S=1/2, I=1/2

P-donor in Si S=1/2, I=1/2

First observation by G. Feher (1958): Electron paramagnetic resonance spectra of phosphorus in silicon-28 FWHM = mT. Natural silicon, FWHM = 0.29 mT V.V. Emtsev Jr., C.A.J. Ammerlaan, A.A. Ezhevskii, A.V. Gusev, Physica B (2006) 45

Isotopic Effects in ESR in Silicon Isotopic effects are caused by changing of nuclear mass: a) Phonon’s frequency shift b) Broadening of spectra is caused by isotopic disordering of the crystal. (In ESR it could contribute to spin-lattice relaxation)

Isotopic effects are caused by changing of nuclear spin I to I≠0 which leads to hyperfine interaction: where a) Hyperfine Fermi–Contact interaction of b) Anisotropic part of hyperfine interaction. Feher (1958)

Isotopic Effects in ESR in Silicon Natural abundances of isotopes for Si, Ge and GaAs Si: 28 Si  =92.27%, I=0 29 Si  =4.68% I=1/2 30 Si  =3.05% I=0 Ge: 70 Ge  =20.55% 72 Ge  =27.37% 73 Ge  =7.67% I=9/2 74 Ge  =7.67% 76 Ge  =7.67% Ga: 69 Ga  =60.2% I=3/2 71 Ga  =39.8% I=3/2 As: 75 As  =100% I=3/2 P: 31 P  =100% I=1/2 N: 14 N  =99.636% I=1 15 N  =0.038% I=1/2 Spin-less GaAs, GaP, GaN (InAs, InP, InN ) couldn’t be obtained!

Isotopic Effects in ESR of Donors in Silicon Deep Donors Centers (Strongly localized electrons) Shallow Donors Centers (electrons localized on hydrogen-like orbital) Low Temperature (T<20K) Shallow Donors Centers (electrons localized on hydrogen-like orbital) Higher Temperatures (20<T<100K) Hopping Conduction Electrons (electrons delocalized into c-band N d <n c (T<100K) Conduction Electrons (electrons delocalized into c-band N d ≥ n c 3d, 4d, 4f, Vacancy-type Defects, Complexes, etc. P, As, Sb, Bi, Li, N, etc. P, As, Sb, Bi, Li, N, etc. P, As, Sb, Bi, Li, N, etc. P, As, Sb, Bi, Li, N, etc. Learning the structure of defects with higher accuracyDetermining the hyperfine contribution to the spin-relaxation ?

Dependence of the full width at half maximum (FWHM) of EPR lines of deep and shallow donor centers in silicon on magnetic nuclear 29 Si concentration. D.V. Guseinov, A.A. Ezhevskii, C.A.J. Ammerlaan, Physica B 381 (2006) 164 D.V. Guseinov, A.A. Ezhevskii, C.A.J. Ammerlaan, Physica B 395 (2007) 65 (ΔB) n = (ΔB sh ) n + (ΔB rel ) n + (ΔB rest ) n, (ΔB sh ) 2 = (2ln2/g 2 μ B 2 )Σ l,i αa l,i 2.

High resolution EPR spectra of Fe 0 in silicon enriched by 28 Si isotope

Li donors in Si-28 Li-O

Conduction electrons in silicon. Spin relaxation. g-factor behavior.

Dependencies of the impurity spin-orbit contribution to the g – factor of conduction electrons on concentration and atomic number of donor Electron on the spin diffusion length L sd, scattered by the n donors, each time getting a g - factor shift  g, such that (  g) 2 = n (  g) 2, where N d1 - number of atoms per unit length.

Hyperfine contribution to the spin relaxation of conduction electrons  t/  t  1,. Тогда: For high concentration of nuclei 29 Si when the electron wave packet covers several nuclei  t becomes meaningless parameter and relaxation rate should be multiplied by the number of nuclei that located within the wave packet.

Measurements were done on Bruker EMX plus 10/12 spectrometer with helium cryostat ( К) ER 4112 HV.

Thank you for your attention

Зависимость ширины линии ЭПР электронов проводимости от температуры для образцов кремния обогащенного изотопом Si-29, легированного фосфором имплантация ионов дозой 6x1012 см-2 (d=1mkm, Nd=6x1016cm-3) дозой 3x1013 см-2 (d=1mkm, Nd=3x1017cm-3)

Saturation curves for EPR lines of conduction electrons for phosphorus doped silicon samples (Si-28 and natural isotopic abundance).