Evidence of hysteresis in a new p-i-n-i-p-i-n amorphous silicon device

A novel device based on a-Si:H p+-i-n--i-p--i-n+ structure, showing a hysteresis in its current-voltage curve is reported. A numerical device model allows to investigate in detail the fundamental role of the two lightly doped n- and p- layers, where charge trapping determines the bistable behavior of the device. The ON condition is maintained until the ambipolar charge injection overcomes the fixed charge. The transition OFF-ON starts when, increasing the applied voltage, one of the two lightly doped layers becomes completely depleted. The transition ON-OFF is, instead, mainly dependent on the recombination processes occurring in the central doped layers. Devices with hysteresis around 2 V and turn-on voltage around 12 are presented