Electron-Spin-Resonance Experiments on Antimony-Doped Germanium

Electron-spin-resonance experiments on shallow donors in germanium are reported. The experiments consist of measurement of the Zeeman effect of the donors as a function of applied uniaxial compression. From the data, a value may be derived for the ratio of the valley-orbit splitting of the donor ground state ($4{\Delta }_c$) to the deformation potential for shear ($E_2$). The results for phosphorus donors agree with determinations by other workers. The result for antimony donors is $\frac{4{\Delta }_c}{E_2}=(2.08\mathrm{}\pm 0.04)\times {10}^{-5\mathrm{}}$. Using the value $E_2=19.2\mathrm{}$ eV leads to a valley-orbit splitting of $4{\Delta }_c=(3.99\mathrm{}\pm 0.2)\times {10}^{-4\mathrm{}}$ eV. This result lies between the values obtained from piezoresistance and spectroscopic measurements. The data require that the singlet state lie below the triplet in antimony donors, just as in phosphorus and arsenic donors. An additional four-line spin-resonance spectrum in antimony-doped germanium is ascribed to donors located near the surface of the samples, in regions of high local strain.