High-injection mobility reduction is examined by theory, modeling, and experimental data acquired by resonance coupled photoconductive decay (RCPCD). The ambipolar mobility is shown to reduce to zero when the constituent injection-dependent carrier mobilities are taken into account. Modeling of the photoconductivity incorporating the transient, injection-dependent, ambipolar mobility confirms experimental reduction in signal at increasing carrier generation rates. The onset of the reduction of mobility occurs at approximately 10 times the background carrier density, thus devices that utilize lightly doped materials are susceptible to anomalous injection based behavior. For photovoltaic applications, high-injection device performance degradation would result from mobility reduction due to lower carrier capture.
Citation: Journal of Solar Energy Materials and Solar Devices
Pub Type: Journals
ambipolar mobility, mobility, photoconductive decay, RCPCD, silicon, solar cells