Negative differential resistance in doped poly(3-methylthiophene) devices

Abstract

The current density–voltage (J–V) characteristics of poly(3-methylthiophene) devices show a negative differential resistance (NDR) at room temperature with a large peak to valley current ratio (∼507). This NDR can be tuned by two orders of magnitude by controlling the carrier density due to the variation of the space-charge region in the device. The temperature and scan rate dependent J–V measurements infer that the NDR is mainly driven by the trapping and de-trapping of carriers. The photo-generation of carriers is observed to reduce the NDR effect.

Current-Voltage Characteristics of the Metal / Organic Semiconductor / Metal Structures: Top and Bottom Contact Configuration Case

“…Considering nature of the negative resistance phenomena observed in present study for some samples it should be mentioned, that negative differential resistance effect was already reported for some organic semiconductor based structures [22][23][24][25][26]. The first one is trapping and de-trapping of carriers [22]. There are proposed two main explanations of the phenomena observed.…”

“…Trap recharging, diffusion of mobile ions, formation and dissociation of bipolarons in the accumulation layer should be considered [20]. Considering nature of the negative resistance phenomena observed in present study for some samples it should be mentioned, that negative differential resistance effect was already reported for some organic semiconductor based structures [22][23][24][25][26]. Considering nature of the negative resistance phenomena observed in present study for some samples it should be mentioned, that negative differential resistance effect was already reported for some organic semiconductor based structures [22][23][24][25][26].…”

“…There are proposed two main explanations of the phenomena observed. Subsequent current decrease at higher voltages is explained by to the strong local heating induced by current flowing via local microconducting channels [22]. However, most authors it explain by presence of the some filamentary microconducting channels.…”

Interface-Driven Multifunctionality in Two-Dimensional TiO2 Nanosheet/Poly(Dimercaptothiadiazole-Triazine) Hybrid Resistive Random Access Memory Device

“…When the polarity changes and the bias is increased from 0 to 1 V, with the help of conductive filament, the carriers from the Ag electrode can be easily injected into TiO 2 -NS, which exhibit Ohmic behavior followed by Mott–Gurney’s or Child’s law behavior. ,, The current decreases from the 0.5 to 0.9 V range, while the bias increases and then gets gradually saturated toward higher voltages. This region in which current decreases with an increase in bias is called negative differential resistance (NDR) (Supporting Information Figure S6d and inset), which can appear whenever charges start filling the traps above a certain threshold voltage and followed by a saturation region. ,,, Beyond the NDR region, the filament starts rupturing due to repulsion of O 2– ions from the Ag (negative biased) and the high barrier at the TiO 2 NS/Ag interface prohibits the efficient injection of carriers, which results in the gradual drop in the current magnitude and eventually the device switches back to HRS. ,,, …”

“…This region in which current decreases with an increase in bias is called negative differential resistance (NDR) (Supporting Information Figure S6d and inset), which can appear whenever charges start filling the traps above a certain threshold voltage and followed by a saturation region. 39,44,50,51 Beyond the NDR region, the filament starts rupturing due to repulsion of O 2− ions from the Ag (negative biased) and the high barrier at the TiO 2 NS/Ag interface prohibits the efficient injection of carriers, which results in the gradual drop in the current magnitude and eventually the device switches back to HRS. 18,40,52,53 To establish further proof of the RS nature, IS measurements were carried out on the TiO 2 -NS device TD; the IS data shows one semicircle in the Cole−Cole plot for both positive and negative bias.…”