Carrier-injection and succeeding pre-channel formation in organic thin-film transistor observed with time-domain reflectometry

Abstract

Carrier-injection and the succeeding pre-channel-formation dynamics in organic thin-film transistor was observed using time-domain reflectometry. Having previously analyzed the depth-wise variation in the initial carrier-injection from the contact electrode to the channel region, we focus here on the succeeding pre-channel-formation dynamics. We demonstrate that a hole concentration in the semiconductor/gate insulator interface increases until its electrical capacitance is filled through contact and access resistances. Thereafter, the injected-hole distribution gradually spreads. A reduction in both contact and access resistances is crucial not only for the static characteristics of the field effect transistor but also the dynamical response.

Initial Photocarrier Generation Process in Organic Photovoltaics Observed with Light‐Triggered Time‐Domain Reflectometry

“…Our research group developed a novel time-resolved electrical measurement for observing transient impedance in the nanosecond time region using time-domain reflectometry (TDR). Our extended time-domain reflectometry (ExTDR) framework was first applied to detect the transient impedance of organic thin-film transistors (OTFTs) [5,6] and organic light-emitting diodes (OLEDs). [7] We succeeded in observing the initial carrier injection process from the contact electrode into the organic thin film by applying a gate voltage in OTFT, or hole exhaust process under reverse bias in the OLED.…”