D- CENTERS PROBED BY RESONANT-TUNNELING SPECTROSCOPY

A donor-related resonance is observed in double-barrier resonant tunne ling devices with Si donors incorporated in the quantum well. In high magnetic fields the resonance becomes dominant over the Is resonance a ssociated with the ground state of a single donor. The bias position o f the donor resonance, its magnetic field dependence, and large amplit ude indicate unambiguously that the resonance is due to tunneling thro ugh the ground state of a shallow donor with two bound electrons (D- l evel).