Energy levels of defects created in silicon supersaturated with transition metals

Abstract

Intermediate-band semiconductors have attracted much attention for use in silicon-based solar cells and infrared detectors. In this work, n-Si substrates have been implanted with very high doses (1013 cm−2 and 1014 cm−2) of vanadium, which gives rise to a supersaturated layer inside the semiconductor. However, the Mott limit was not exceeded. The energy levels created in the supersaturated silicon were studied in detail by means of thermal admittance spectroscopy. We found a single deep center at energy near EC − 200 meV. This value agrees with one of the levels found for vanadium in silicon. The capture cross-section values of the deep levels were also calculated, and we found a relationship between the capture cross-section and the energy position of the deep levels which follows the Meyer–Neldel rule. This process usually appears in processes involving multiple excitations. The Meyer–Neldel energy values agree with those previously obtained for silicon supersaturated with titanium and for silicon contaminated with iron.