Optimizing the photoresponse enhancement in a hybrid inorganic–organic phototransistor with an amorphous indium gallium zinc oxide channel layer and PTCDI-C13 photoactive layer

Abstract

Amorphous metal oxide semiconductors offer high performance and versatility for new generation electronic devices. On the other hand, their applicability to optoelectronics is limited by their wide bandgap. Organic semiconductors offer a strong photoresponse to visible light but have relatively low charge carrier mobility. This paper presents inorganic–organic hybrid phototransistors employing amorphous indium gallium zinc oxide (a-IGZO) as a channel layer with a highly photoresponsive perylene derivative organic photoactive layer. The fabrication conditions were optimized to yield devices with high electrical performance and provide a proper organic–inorganic interface for the photogenerated charges to be transported efficiently into the channel layer to increase the photocurrent significantly compared to bare a-IGZO. The photoresponse was evaluated by measuring the device characteristics in the dark and under illumination. The devices were compared based on the shift in the threshold voltage as a function of the irradiance and illumination time. The dynamic photoresponse of the devices under a discrete light pulse was evaluated in detail. The optimal device had a channel layer annealed at 500 °C, which provided relatively high mobility and a significantly higher photocurrent than the bare a-IGZO devices.