Enhanced Photo Sensing and Lowered Power Consumption in Concentric MIS Devices by Monitoring Outer Ring Open-Circuit Voltage With Biased Inner Gate

Concentric metal-insulator-semiconductor (MIS) structure is used as a photo sensor. Generally, the outer ring acts as gate and the inner circle acts as sensor. In this article, by changing the sensing method from measuring light current to measuring open-circuit voltage of floating sensor, power consumption is considerably lowered. Moreover, by exchanging conventional role of inner device and outer ring, photo-sensitivity under extremely weak light is also highly enhanced, and it results from asymmetric coupling effect of inner circle and outer ring. Furthermore, our device shows great performance as well when using light current as alternative sensing signal in the conventional way.