Anomalous Current Decrease Under Illumination in Ambipolar Phototransistors Based on PTCDI‐C5 Crystals Embedded in C8‐BTBT Thin Film. (6th January 2021)

• Record Type: Journal Article
• Authors: Tarsoly, Gergely; Choi, Youngill; You, Young Gyu; Jhang, Sung Ho; Pyo, Seungmoon
• Is Part Of: Advanced Electronic Materials. Volume 7:Number 2(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-01-06
• Subjects: charge trapping -- organic field‐effect transistors -- organic phototransistors -- organic semiconductors -- photogating -- photogenerated charge carriers -- polymer gate dielectrics; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.202000973
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract: Most organic thin film‐based phototransistors exhibit an increase in current under illumination owing to the trapped photogenerated minority charge carriers, which enhance the accumulation of majority carriers in the semiconductor layer of the device. Recent research reveals that, on employing a unique active layer structure, phototransistor devices exhibit abnormal photoresponse behaviors under certain conditions: hole‐dominated current decreases under illumination and shows an anomalous dependence on irradiance. The current decreases with increasing irradiance. When the irradiance is increased further, a moderate current increase is observed. Under a constant negative bias, when a discrete light pulse is turned on, the current decreases sharply and then slowly increases to saturation in the beginning and it starts to increase when illumination is ceased. These anomalies are analyzed, and the changes in current are modeled using a mathematical model based on the simultaneous trapping and release of both photogenerated holes and electrons. Abstract : A phototransistor with organic semiconductor layer composed of crystal‐array embedded in thin film exhibits anomalous current drop under negative bias with non‐monotonic irradiance dependence. A discrete light pulse induces a sharp current decrease followed by a subsequent increase. The anomalous photoresponse is found to be the result of simultaneous trapping and release of photogenerated holes and electrons.