TRANSIENT PHOTOCONDUCTIVITY OF A-SE MEASURED BY THE TIME-OF-FLIGHT AND STRIPLINE-SWITCH TECHNIQUES - A COMPARATIVE-STUDY

We present the results of a comparative study of transient photoconductivity of a-Se measured by time-of-flight and stripline-switch techniques. Measurements in the time-of-flight configuration reveal a thermally activated transport, exponential dependence of the photocurrent on bias voltage, and a strong dependence on photon energy-features which are the hallmarks of a transport in metal-semiconductor diode junctions. In contrast, the transient photoconductivity in the stripline switch configuration is temperature independent and is not significantly affected by the metallic contacts. We thus find transient photoconductivity measurements in the time-of-flight configuration useful for investigating carrier dynamics in metal-semiconductor junctions, but prefer the stripline-switch technique for investigating the functional dependence of the quantum yield on various parameters such as temperature, photon energy, etc.