AMSM 2024, Incheon, Korea

October 27 - October 30, 2024 (Sun. - Wen.), Songdo ConvensiA

AMSM 2024, Incheon, Korea

October 27 - October 30, 2024 (Sun. - Wen.), Songdo ConvensiA

Abstract

Organic photodiodes are ideal for advanced flexible electronic applications such as imaging and video photography due to their tunable photophysical properties, low-cost and simple processing methods, and continuously improving performance. In particular, the simple design and thin thickness of organic material-based devices enable the control of optical and geometrical crosstalk, garnering attention for application in image sensors. Utilizing these organic photodiodes in image sensors necessitates their integration into high-density arrays. This approach is essential for achieving the precise and effective performance required for advanced imaging applications. However, the absence of precise pixelation techniques capable of implementing organic light-emitting semiconductor with high production and reliability has limited the realization of high-density organic photodiodes. In this paper, we present a silicone engineered anisotropic lithography of the organic light-emitting semiconductor (OLES) that in-situ forms a non-volatile etch blocking layer during reactive ion etching. This unique feature not only slows the etch rate but also enhances the anisotropy of etch direction, leading to gain delicate control in forming ultrahigh-density multicolor OLES patterns (minimum line width of 2µm) through photolithography. This patterning strategy inspired by silicon etching chemistry is expected to provide new insights into high-density organic photodiodes. Furthermore, the proposed system is expected to be applicable to flexible substrates, extending its use to soft sensor applications such as artificial eyes.

AMSM 2024, Incheon, Korea

October 27 - October 30, 2024 (Sun. - Wen.), Songdo ConvensiA

Monolithic VOC Sensor Circuit Based on a-IGZO TFT

Kyungmin Choi, Keun-Yeong Choi, and Hojin Lee

Abstract

Volatile organic compounds (VOCs) generated in industrial production lines are harmful to human health, prompting significant research into detecting VOC gases. For detection of various VOCs, Amorphous oxide semiconductors (AOS) have been highly researched to achieve high-sensitivity chemo-resistive-type VOCs gas sensors. Especially, amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) are attracting high attention due to their high field-effect mobility, low leakage current, good uniformity, and superior electrical stability at low processing temperatures. In this paper, we propose a monolithic sensor circuit designed to amplify the sensing signal of solution-processed a-IGZO sensor TFTs, achieving high sensitivity. The fabricated a-IGZO sensor TFT showed significant changes in transfer characteristics upon exposure to acetone gas, with decreased resistance and a negative threshold voltage shift. The proposed circuit, comprising three a-IGZO TFTs and one capacitor, demonstrated successful gas sensing through simulation, confirming accurate operation. Through this study, we confirmed that the proposed a-IGZO TFT sensor circuit was successfully operated with accurate gas sensing operations. It is expected that the proposed monolithic sensor circuit can be applied to future VOCs systems with highly sensitive detection.

CLEO 2019, San Jose, California, USA

May 10 - 15, 2019 (Mon. - Fri.), San Jose Convention Centor

Terahertz Single-Pixel Imaging System with Electrically Tunable Metamaterial Spatial Light Modulator

Wonwoo Lee, Hyunseung Jung, Hyunwoo Jo, Moon Sung Kang, and Hojin Lee

Abstract

  Due to its penetrability and straightness of terahertz wave, terahertz imaging system has been extensively studied for real-time, high-resolution and accurate imaging systems. However, these imaging systems require high power sources or expensive and complex detectors and usually take a long time to acquire a single image. To overcome the limitations mentioned before, a single-pixel imaging system that had been used in optical imaging technique has been introduced into the terahertz range. In particular, through a single-pixel imaging system, it is possible to construct a terahertz imaging system using only a lamp and a bolometer detector instead of telescopic systems consisting of hundreds of terahertz parts, which gives great possibility for commercialization. In this work, we present electrically tunable terahertz spatial light modulator (SLM) based on ion-gel gating graphene metamaterials. From experimental results, we confirmed that the terahertz image could be successfully reconstructed corresponding to 93 % with the real object image at maximum.

CLEO 2022, San Jose, USA

May 16 - May 20, 2022 (Mon. - Fri.), McEnery Convention Center