Boosting Responsivity of Organic-Metal Oxynitride Hybrid Heterointerface Phototransistor

Amorphous metal oxides are attractive materials for various sensor applications, because of high electrical performance and easy processing. However, low absorption coefficient, slow photoresponse, and persistent photoconductivity of amorphous metal oxide films from the origin of deep-level defects are obstacles to their use as photonic applications. Here, we demonstrate ultrahigh photoresponsivity of organic-inorganic hybrid phototransistors featuring bulk heterojunction polymers and low bandgap zinc oxynitride. Spontaneous formation of ultrathin zinc oxide on the surface of zinc oxynitride films could make an effective band-alignment for electron transfer from the dissociation of excitons in the bulk heterojunction, while holes were blocked by the deep highest occupied molecular orbital level of zinc oxide. These hybrid structure-based phototransistors are ultrasensitive to broad-bandwidth photons in ultraviolet to near infrared regions. The detectivity and a linear dynamic range exceeded 10(12) Jones and 122.3 dB, respectively.This work was financially supported by a grant from the National Science Foundation (Grant No. CHE-1230598, Program Manager Linda S. Sapochak), the Office of Naval Research (Program Manager Dr. Paul Armistead; Grant No. N000141410648), and UCLA internal funds. This research was also supported by Global Frontier Program through the Global Frontier Hybrid Interface Materials (GFHIM) of the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2013M3A6B1078870) and done by the MOTIE (Ministry of Trade, Industry & Energy (Grant No. 10051403) and KDRC (Korea Display Research Corporation) support program for the development of future devices technology for display industry