On Injection in Intrinsic Single-Carrier Devices

By considering the changes in the interface charge-carrier densities of a single-carrier device as a function of injection-barrier heights and comparing these to the equilibrium, background charge-carrier density of a device with Ohmic contacts, we calculate simple conditions for when these barriers are expected to limit injection and therefore significantly affect space-charge-limited currents in the device. We show that these conditions depend on the device temperature, the semiconductor relative permittivity and effective density if states, but most importantly the thickness of the semiconducting film being probed. This is in accordance with previous observations and similar derived expressions for when defects influence single-carrier devices. The conditions described herein can be used to aid in the design of single-carrier devices for space-charge-limited current measurements that are not limited by injection.Comment: 12 pages, 4 colour figures, no supplementary information documen