Yoo Hyukjoon, Kim Won-Gi, Kang Byung Ha, Kim Hyung Tae, Park Jeong Woo, Choi Dong Hyun, Kim Tae Sang, Lim Jun Hyung, Kim Hyun Jae
School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.
Frontier Technology Team, Display Research Center, Samsung Display, 1 Samsung-ro, Giheung-gu, Yongin-si, Gyeonggi-do 17113, Republic of Korea.
ACS Appl Mater Interfaces. 2020 Mar 4;12(9):10673-10680. doi: 10.1021/acsami.9b22634. Epub 2020 Feb 24.
Visible light can be detected using an indium-gallium-zinc oxide (IGZO)-based phototransistor, with a selenium capping layer (SCL) that functions as a visible light absorption layer. Selenium (Se) exhibits photoconductive properties as its conductivity increases with illumination. We report an IGZO phototransistor with an SCL (SCL/IGZO phototransistor) that demonstrated optimal photoresponse characteristics when the SCL was 150 nm thick. The SCL/IGZO phototransistor exhibited a photoresponsivity of 1.39 × 10 A/W, photosensitivity of 4.39 × 10, detectivity of 3.44 × 10 Jones, and external quantum efficiency of 3.52 × 10% when illuminated by green light (532 nm). Ultraviolet-visible spectroscopy and ultraviolet photoelectron spectroscopy analysis showed that Se has a narrow energy band gap, in which visible light is absorbed and forms a p-n junction with IGZO so that photogenerated electron-hole pairs are easily separated, which makes recombination more challenging. We show that electrons generated in the SCL flow through the IGZO layer, which enables the phototransistor to detect visible light. Furthermore, the SCL/IGZO phototransistor exhibited excellent durability and reversibility owing to the constant light and dark current and the time-dependent photoresponse characteristics over 8000 s when a red light (635 nm) source was turned on and off at a frequency of 0.1 Hz.
使用基于铟镓锌氧化物（IGZO）的光电晶体管可以检测可见光，该晶体管具有用作可见光吸收层的硒覆盖层（SCL）。硒（Se）具有光电导特性，因为其电导率随光照增加。我们报道了一种带有SCL的IGZO光电晶体管（SCL/IGZO光电晶体管），当SCL厚度为150 nm时，该晶体管表现出最佳的光响应特性。当用绿光（532 nm）照射时，SCL/IGZO光电晶体管的光响应度为1.39×10 A/W，光敏度为4.39×10，探测率为3.44×10琼斯，外量子效率为3.52×10%。紫外可见光谱和紫外光电子能谱分析表明，Se具有窄的能带隙，在其中可见光被吸收并与IGZO形成p-n结，从而使光生电子-空穴对易于分离，这使得复合更具挑战性。我们表明，在SCL中产生的电子流经IGZO层，这使得光电晶体管能够检测可见光。此外，当以0.1 Hz的频率打开和关闭红光（635 nm）光源时，由于恒定的亮电流和暗电流以及超过8000 s的随时间变化的光响应特性，SCL/IGZO光电晶体管表现出优异的耐久性和可逆性。
