The Time Dependence of Currents in MISIM Structures with ZnS: Mn Active Layers

Abstract

The shapes of current versus time curves in ZnS: Mn MISIM structures are studied in dependence on voltage, temperature, and Mn concentration. The experimental curves compare well with those computed on the basis of a tunneling model which takes into account the presence of the internal field due to bulk ionized centres and the filling level of the interface states.

Interface charge relaxation in ZnS:Mn based alternating-current thin-film electroluminescent devices

“…The inner transferred charge can be further found from the corresponding semiconductor-insulator capacitance ratio. 4,6,8 Obviously, the transferred charge also decreases if the frequency decreases. In fact, this decrease is not related to the pulse period but only to the interval between the pulses ͑the rest time͒.…”

“…6,7 In particular, the parameters corresponding to the interface states and other material characteristics are the same. For instance the value of N s0 is 2 ϫ10 13 cm Ϫ2 eV Ϫ1 and that of E 0 is 1.6 eV.…”

“…͑1͒-͑10͒ and of those connected to them. 6,7 The set of values corresponding to different rest times is finally compared with the experimental one. Thus, the iteration procedure allows for the determination of a set of A , B , and w A values yielding the best fitting with the experimental data corresponding to the lowest voltage amplitude.…”

“…These features allow us to obtain well-defined shapes for the active current pulses that, in this way, can be correctly compared with the computed ones. 6,7 These pulses were obtained using a special built generator whose schematic diagram is presented in Fig. 1.…”

“…1 It was intensively investigated in the past years so that the main processes that determine the electrical and optical characteristics of the device were quite well established. [2][3][4][5][6][7] Thus it was shown that the electrons from the insulatorsemiconductor interface are tunnel injected in the conduction band of the ZnS. During their moving through the semiconductor layer some processes as multiplication, recombination, and optical center excitation take place.…”