a-Si:H, to or from a-Si, Ge:H, F graded-bandgap structures

The optoelectronic properties of graded-bandgap a-Si:H, F to or from a-Si, Ge:H, F semiconductor structures were studied by the time-of-flight technique and by the voltage-bias dependence of the photocurrent. The mobility-lifetime ( mu tau ) products for both electrons and holes depend strongly on the compositional grading. Values of mu tau that are higher than in bulk alloys with the same effective optical bandgap can be obtained. With graded-gap amorphous structures, the electron and hole transport properties can be tuned independently.<
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