Majority and minority carrier lifetimes in doped a-Si junctions and the energy of the dangling-bond state

Abstract

Electron and hole lifetimes have been measured by transient-delayed-field techniques on a series of a-Si junction specimens deposited with lightly doped n- or p-type central regions. The results, plotted as a function of Fermi level position, show a pronounced sensitization of the majority carriers and a desensitization of the minority carriers. The data are readily explained by electron and hole capture at the dangling-bond centre. An analysis of this centre in terms of the occupation statistics places it at an energy between 0·95 and 1·0 eV below ε_c. The assignment is supported by independent results, but disagrees with recent spectroscopic work.