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HL: Halbleiterphysik

HL 11: Kohlenstoff / Diamant

HL 11.9: Vortrag

Montag, 26. März 2001, 17:30–17:45, S17

Sulfur doping in diamond: n-type behavior and electronic structure — •J.A. Garrido¹, C.E. Nebel¹, M. Stutzmann¹, E. Gheeraert², and A. Deneuville² — ¹Walter Schottky Institut, Am Coulombwall, 85748 Garching, Germany — ²LEPES-CNRS, Avenue des Martyrs, 38042 Grenoble Cedex, France

Sulfur-doped diamond was investigated in order to determine if sulfur is a shallow donor in diamond. Hall measurements were carried out in the temperature range 175K-350K, and a clear n-type behavior was found. An electron concentration of 5.6x10¹² cm⁻³ with a mobility of 270 cm²V⁻¹s⁻¹ was measured at room temperature. An activation energy of around 400 meV was extracted from the Hall-effect measurements. The electronic structure of the sulfur level was studied for the first time using photoconductivity spectroscopy. Phonon-assisted oscillatory features were observed in the low-temperature spectra, due to the fast capture of electrons by the excited states of sulfur by LO-phonon emission. The electronic transitions between the ground level and the excited states were found to occur at the energies 353meV, 386meV, 408meV, 451meV, and 471meV. From the photoconductivity experiment, the position of the ground state was found to be around 480 meV. The present paper clearly confirms the donor character of sulfur in diamond.