Design of Low Molecular Organic Photodiode: Top Light Absorption and Bottom Light Absorption

Abstract

CMOS image sensor (CIS) is used not just camera which capture people's memory but also protecting their worthy things. In addition, it has become a key part of many devices that perform tasks on behalf of the human’s eye during the fourth industrial revolution era. As the demand for high pixel camera increases, the size of the photodiodes naturally becomes smaller. The photodiode size getting smaller, crosstalk becomes inevitable phenomenon. When light goes through the color filter, a little of light travel adjacent photodiode which makes a false output signal. In this study, organic photoconductive material is used to overcome this limit. CIS using organic material has been studied in many ways. But there are many issues remain. One of the challenges in improving of organic CIS is its contact between metal-organic(M/O) and organic-metal(O/M). In order to achieve high performance, there must lower charge injection barrier height and minimize the localized trap states at the M/O and O/M interface. In this study, 5,12-Dihydro-5,12-dimethylquino[2,3-b]acridine-7,14-dione (DMQA) and N,N’-Dimethyl-3,4,9,10-perylenedicarboximide (MePTC) are used for green sensitive organic materials. Mixed molybdenum oxide (MoOx), aluminum (Al) and nickel oxide (NiOx) are used for optimizing M/O and O/M interface. In the initial study, materials were stacked in the order of indium tin oxide (ITO), organic material, and Al (standard structure). And the same order of deposition was applied to Al, organic materials and ITO (inverted structure). In this study, M/O interface which between ITO and organic in standard structure, and Al and organic materials in inverted structure is called bottom interlayer and O/M interface which between organic materials and Al in standard structure, and organic materials and ITO in inverted structure. All experiments are proceeded on the glass substrate.