R. Ghez, M.B. Small
JES
A simple model is presented for calculating the photoionization cross-section spectra of a two-electron center in silicon. A hydrogenlike wave function is used for the ground state of the singly ionized one-electron center, and a heliumlike wave function for the ground state of the neutral two-electron center. A test of this model is provided by comparison with the observed photoionization cross-section spectra of sulfur centers in silicon, using trial wave functions obtained previously from variational calculations of the bound-state electronic energy levels. The experimental spectra were obtained by the photocapacitance transient method for sulfurdoped silicon p+-n junction diodes. Good agreement between theory and experiments is obtained without the use of empirical-effective-field ratios. Structures below the extrinsic edge in the spectra of the neutral centers were observed and are attributed to two-step photothermal transitions. The peak at about 0.285 eV is attributed to an optical transition from the [1 s(A1),1 s(A1)] ground state of the neutral two-electron center to the [1 s(A1),1 s(T2)] excited state, with a subsequent thermal excitation into the conduction band as the second transition step. © 1976 The American Physical Society.
R. Ghez, M.B. Small
JES
B.A. Hutchins, T.N. Rhodin, et al.
Surface Science
Arvind Kumar, Jeffrey J. Welser, et al.
MRS Spring 2000
Robert W. Keyes
Physical Review B