Transformation from Ohmic to offset behavior for the on state of an amorphous semiconductor threshold switch for interruptions greater than 12 ns

In measuring the on-state I-V curve of an amorphous semiconductor threshold switch it is essential that the addressing voltage pulse does not allow a subholding voltage interval which is longer than a ’’distribution free carrier lifetime’’ in order that only on-state properties be detected. If the voltage is not allowed to fall beneath the holding level for longer than about 12 ns, the well-known offset barrier of the transient on characteristics (TONC) does not develop, and, instead, the on-state curve is linear and largely temperature independent. The time interval τ1≈12 ns is interpreted as the distribution free carrier lifetime, or the average time interval of subholding voltage during which a sufficient number of carriers can either redistribute across the device, or can recombine into traps, to initiate the development of the offset barrier voltage in the TONC. The offset voltage, or what is called the blocked on state or the transient off state, is thus not a true element of the metal-like on state and is instead representative of the semiconductive intermediate states which bridge the normal off state and the true on state and which may involve a screening condition.