새소식

Department of Physics & Astronomy

[심진우 학부생/유성규 학생/이탁희 교수] 페로브스카이트 나노 결정-이황화몰리브덴 이형 접합을 활용한 광 검출 성능 향상 연구 (ACS Nano 게재)

2024-06-24l 조회수 1012

Enhanced Photodetection Performance of In Situ Core/Shell Perovskite-MoS2 Phototransistor

이차원 전이금속 디칼고게나이드(transition metal dichalcogenide, TMDC) 기반 광 트랜지스터(phototransistor)는 높은 집적도와 유연성을 제공할 수 있어 잠재성이 크지만, 매우 얇은 두께로 인한 낮은 흡광도를 가져 높은 광 반응성을 얻는데 한계가 있다. 본 연구에서는 표면 결함(surface defect)을 최소화하고 광 캐리어(photocarrier) 주입을 향상시키는 인-시츄 코어/쉘 페로브스카이트(in situ core/shell perovskite)- 이황화몰리브덴(molybdenum disulfide, MoS2) 이형 접합을 활용해 높은 광 검출 성능을 얻었다. 더 나아가 소자의 주요 작동 원리가 광 전도 효과(photoconductive effect)와 광 게이팅 효과(photogating effect)임을 보이고, 최적의 작동 조건을 찾았다. 본 연구는 이차원 소재와 페로브스카이트의 장점을 모두 활용해 고성능의 광 트랜지스터 개발을 위한 유망한 경로를 제시한다.  논문의 1저자인 심진우, 유성규 학생은 이탁희 교수 연구실의 학부인턴으로 연구를 수행하였다. 심진우 학생은 올해 가을 미국 MIT 전자공학과 박사과정 진학을 앞두고 있으며, 유성규 학생은 올해 봄부터 우리 학부에서 대학원 과정을 밟고 있다.

While two-dimensional transition metal dichalcogenides (TMDCs)-based photodetectors offer prospects for high integration density and flexibility, their thinness poses a challenge regarding low light absorption, impacting photodetection sensitivity. Although the integration of TMDCs with metal halide perovskite nanocrystals (PNCs) has been known promising for photodetection with high absorption coefficient of PNCs, the low charge mobility of PNCs delays efficient photocarrier injection into TMDCs. In this study, we integrated MoS2 with in situ formed core/shell PNCs with short ligands that minimize surface defects and enhance photocarrier injection. The PNCs/MoS2 heterostructure efficiently separates electrons and holes by establishing type II band alignment and consequently inducing a photogating effect. The synergistic interplay between photoconductive and photogating effects yields a high responsivity of 2.2 106 A/W and a specific detectivity of 9.0 1011 Jones. Our findings offer a promising pathway for developing low-cost, high-performance phototransistors leveraging the advantages of 2D materials.

Authors: Jinwoo Sim,|| Sunggyu Ryoo,|| Joo Sung Kim,|| Juntae Jang, Heebeom Ahn, Donguk Kim, Joonha Jung, Taehyun Kong, Hyeonmin Choi, Yun Seog Lee, Tae-Woo Lee,* Kyungjune Cho,* Keehoon Kang,* and Takhee Lee* (||Equally first authors, *co-corresponding authors)

DOI: https://doi.org/10.1021/acsnano.4c02775
Published online: June 21, 2024
Link: https://pubs.acs.org/doi/full/10.1021/acsnano.4c02775