Energy Levels of Defects Created in Silicon Supersaturated with Transition Metals

Abstract

Intermediate band in semiconductors have attracted much attention for their use in silicon-based solar cells and infrared detectors. In this work, n-Si substrates were implanted with very high doses (10 13 and 10 14 cm -2 ) of vanadium, which gives rise to a supersaturated layer inside the semiconductor. However, the Mott limit was not overtaken. The energy levels created in the supersaturated silicon were studied in detail by means of thermal admittance spectroscopy. We have found a single deep center at an energy of E C -250 meV or E C -200 meV depending on the dose. 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 agrees with the ones previously obtained for silicon supersaturated with titanium and for silicon contaminated with iron.

Hyperdoped silicon materials: from basic materials properties to sub-bandgap infrared photodetectors

“…In their work, a broad array of deep levels associated with the manufacturing process were identified within the substrate depletion layer of photodiodes fabricated based on Si:Au. Similar results were obtained by Castán et al [151], Pérez et al [141,152] and García et al [153] when analyzing Si:Ti or Si:V diodes by using the thermal admittance spectroscopy technique. Particularly, for the Si:Au sample, the authors focus their attention on the E 1 level that is 0.35 eV below the conduction band edge.…”