Photogating-based Organic Synapse Electronics Modulated by Dielectric

The greatest strength of photogating effect is that the current level can be adjusted by light. Research on photogating effect is still actively underway, and various factors play a role in causing photo-reaction. In general, they work in such a way that photo-generated carriers generated under certain conditions are trapped, leading to threshold voltage shifts. Here we focus on the surface environment in which photocarriers are trapped/de-trapped. To analyze the difference in photo-response depending on the insulating layer of the phototransistor, we produced a DNTT TFTs with a SiO2 dielectric and a DNTT TFTs with a TiO2/SiO2 dielectric. Except for the insulating layer, the channel and source/drain electrodes use dinaphtho[2,3-b:2′,3′- f]thieno[3,2-b]thiophene (DNTT) and Au. 500 nm and 600 nm irradiation allowed a gradual current rise while DNTT TFTs with a TiO2/SiO2 dielectric allowed fast de-trapping. Additionally, facial recognition synapse simulation using 500 nm and 600 nm light using a DNTT TFTs with a TiO2/SiO2 dielectric achieved recognition rates of over 90%.