Multiple subthreshold swing circuit and application to displays and sensors

An apparatus, comprising:

• a junction field-effect transistor (JFET) comprising:
• a first layer comprising silicon having a first type of carrier as its majority carrier;
• a gate comprising a second layer formed on the first layer, the second layer comprising intrinsic amorphous hydrogenated silicon, a third layer formed on the second layer, the third layer comprising amorphous hydrogenated silicon having a second type of carrier as its majority carrier, and a conductive layer formed on the third layer;
• and
• first and second terminals, each of the first and second terminals comprising a fourth layer formed on the first layer, the fourth layer comprising crystalline hydrogenated silicon having the first type of carrier as its majority carrier, and a conductive layer formed on the fourth layer;
• and
• a set of one or more serially-connected diodes, each diode having first and second terminals, wherein the first terminal of a first diode in the set of one or more serially-connected diodes is connected to the second terminal of the JFET;
• wherein the gate of the JFET is not directly connected with the set of one or more serially-connected diodes.