Session:

Hemispherical image sensors simplify lens designs, reduce optical aberrations, and improve image resolution for compact wide-field-of-view cameras. To achieve hemispherical image sensors, organic materials are promising candidates due to the following advantages: tunability of optoelectronic/spectral response and low-temperature low-cost processes. Here, we developed a photolithographic process to prepare a hemispherical image sensor array using organic thin film photo-memory transistors with a density of 308 pixels per square centimeter. Our design includes only one photo-memory transistor as a single active pixel, in contrast to the conventional pixel architecture, consisting of select/readout/reset transistors and a photodiode. Our organic photo-memory transistor, comprising light-sensitive organic semiconductor and charge-trapping dielectric, is able to achieve linear photo-response (light intensity range, from 1 to 50 W m^-2), along with responsivity as high as 1.6 A W^-1 (wavelength = 465 nm) for a dark current of 0.24 A m^-2 (drain voltage = -1.5 V). These observed values represent the best responsivity for similar dark currents among all the reported hemispherical image sensor arrays to date. We further developed a transfer method that does not damage organic materials for hemispherical organic photo-memory transistor arrays. Our developed techniques are scalable and are amenable for other high-resolution 3-dimensional organic semiconductor devices.

Co-Author(s): Chenxin Zhu (Stanford University), Wen-ya Lee (Stanford University), Anna Smith (University at Buffalo, The State University of New York), Haowen Ma (Nanjing University), Xiang Li (Nanjing University), Donghee Son (Stanford University), Naoji Matsuhisa (Stanford University), Jaemin Kim (Stanford University), Won-Gyu Bae (Stanford University), Sung Ho Cho (Samsung Display), Myung-Gil Kim (Stanford University), Tadanori Kurosawa (Stanford University), Toru Katsumata (Asahi Kasei), John To (Stanford University), Jin Young Oh (Stanford University), Seonghyun Paik (Stanford University), Soo Jin Kim (Stanford University), Lihua Jin (Stanford University), Feng Yan (Nanjing University), Jeffrey Tok (Stanford University), Zhenan Bao (Stanford University)

Yeongin Kim

University of Cincinnati

Appearances