Determination of the capture cross sections of electrons in undoped hydrogenated amorphous silicon from the photoconductivity of and space-charge relaxation in n(+)-i-n(+) structures; the role of light exposure and annealing

摘要

Electron capture cross sections. sigma (c), in standard hydrogenated amorphous silicon deposited at 150 degreesC are determined from photoconductivity (PC) and space-charge-relaxation (SCR) measurements. A good correlation is observed between the values obtained by the two techniques. The validity of the methods used is tested by varying sigma (c) over a large range by light-soaking. It is shown that the capture cross sections depend strongly on the density of states at the Fermi level N(E-F); in fact, sigma (c) increases by nearly two orders of magnitude when N(E-F) increases by only a factor of five. The PC and SCR studies both account for this large increase. [References: 18]