Optimized laser scanned photodiode (LSP) imaging transducer

An optimized ZnO:Al/a-pin SixC1-x:H/Al configuration for the laser scanned photodiode (LSP) imaging detector is proposed. The LSP utilizes self-field-induced depletion layers as detector and a laser beam for readout. The effect of the sensing element structure, cell configuration and light source flux are investigated and correlated with the sensor output characteristics. Experimental data reveal that the large optical gap and the low conductivity of the doped a-SixC1-x:H layers are responsible for an induced inversion layer at the illuminated interfaces which blocks the carrier collection. These insulator-like: layers act as MIS gates that prevent excess signal charge from spreading to the nearby dark regions, which would lead to image smearing. The physical background of the LSP is discussed.