Resistive Switching by Percolative Conducting Filaments in Organometal Perovskite Unipolar Memory Devices Analyzed Using Current Noise Spectra
유무기 페로브스카이트 물질을 기반으로 한 저항 변화 메모리 소자는 저전압 동작 및 높은 ON/OFF ratio와 같은 뛰어난 메모리 특성을 나타낸다. 본 연구에서는 페로브스카이트 메모리의 저항변화 특성과 메커니즘을 전류 노이즈를 통해 분석하였다. Percolation 모델을 통해 각 저항 상태에서의 노이즈 신호의 scaling 특성은 특정한 프랙탈 차원을 가지는 페로브스카이트 내부 전도성 필라멘트 구조와 연관 지어 이해할 수 있었다. 본 연구는 페로브스카이트 물질의 저항변화 현상에 대한 이해를 향상시키고 메모리 소자의 성능 향상에 기여할 것으로 기대된다.
Organometal halide-perovskite resistive memory has the advantage of operating with a low voltage and large on/off ratio. However, random operation characteristic due to the stochastic formation of conducting filaments remains a challenge in memory application. Therefore, it is essential to investigate the formation and dissolution of conducting filaments and their structure. However, direct observation of a nanoscale filamentary structure is often challenging. Moreover, detailed studies of conducting filaments in the halide-perovskite materials have rarely been reported. By employing a scaling theory with a fractal structure, this study investigates the geometric structures and dynamics of conducting filaments formed in organometal halide perovskite through current noise analysis. The temperature-dependent electrical properties and current noise demonstrate the role of ion migration in the formation of conducting filaments. This study can enhance the understanding of the resistive switching phenomena of perovskite resistive memory devices in terms of percolative conducting filaments. Thus, providing a route for achieving a stable memory operation by controlling the relevant structure and dynamics of the switching processes.
Authors : Heebeom Ahn†, Keehoon Kang†*, Younggul Song, Woocheol Lee, Jae-Keun Kim, Junwoo Kim, Jonghoon Lee, Kyeong-Yoon Baek, Jiwon Shin, Hyungbin Lim, Yongjin Kim, Jae Sung Lee* and Takhee Lee*
DOI: 10.1002/adfm.202107727
Published online: September 23, 2021
https://onlinelibrary.wiley.com/doi/10.1002/adfm.202107727
