Aging effects in microcrystalline silicon films studied by transient photoconductivity

TY - JOUR

T1 - Aging effects in microcrystalline silicon films studied by transient photoconductivity

AU - Smirnov, V.

AU - Reynolds, S.

AU - Main, C.

AU - Finger, F.

AU - Carius, R.

PY - 2004/6

Y1 - 2004/6

N2 - Measurements of dark conductivity, steady-state and transient photoconductivity in undoped and boron-doped microcrystalline silicon films exposed to room air are reported. Two aging processes are identified: (i) an increase in dark conductivity and mobility-lifetime product occurring over several days, that may be reversed by heating to 160 °C under vacuum, and subsequently re-cycled, (ii) an irreversible change in the density of states occurring over a period of several months. It is proposed that the reversible effect is associated with charge transport in a region of electron accumulation induced by weakly-adsorbed water, whereas the irreversible effect, identified from its transient photocurrent signature, is associated with a true change in the density of states within the transport path, possibly as a result of slow chemical reactions at silicon grain boundaries.

AB - Measurements of dark conductivity, steady-state and transient photoconductivity in undoped and boron-doped microcrystalline silicon films exposed to room air are reported. Two aging processes are identified: (i) an increase in dark conductivity and mobility-lifetime product occurring over several days, that may be reversed by heating to 160 °C under vacuum, and subsequently re-cycled, (ii) an irreversible change in the density of states occurring over a period of several months. It is proposed that the reversible effect is associated with charge transport in a region of electron accumulation induced by weakly-adsorbed water, whereas the irreversible effect, identified from its transient photocurrent signature, is associated with a true change in the density of states within the transport path, possibly as a result of slow chemical reactions at silicon grain boundaries.

U2 - 10.1016/j.jnoncrysol.2004.03.010

DO - 10.1016/j.jnoncrysol.2004.03.010

M3 - Article

SN - 1873-4812

VL - 338

SP - 421

EP - 424

JO - Journal of Non-Crystalline Solids

JF - Journal of Non-Crystalline Solids

ER -