Kim Jaeyoung, Cho Kyungjune, Pak Jinsu, Lee Woocheol, Seo Junseok, Kim Jae-Keun, Shin Jiwon, Jang Juntae, Baek Kyeong-Yoon, Lee Jonghoon, Chung Seungjun, Kang Keehoon, Lee Takhee
Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
Soft Hybrid Materials Research Center, Korea Institute of Science and Technology, Seoul 02792, Korea.
ACS Nano. 2022 Apr 26;16(4):5376-5383. doi: 10.1021/acsnano.1c08104. Epub 2022 Apr 4.
Recently there has been growing interest in avalanche multiplication in two-dimensional (2D) materials and device applications such as avalanche photodetectors and transistors. Previous studies have mainly utilized unipolar semiconductors as the active material and focused on developing high-performance devices. However, fundamental analysis of the multiplication process, particularly in ambipolar materials, is required to establish high-performance electronic devices and emerging architectures. Although ambipolar 2D materials have the advantage of facile carrier-type tuning through electrostatic gating, simultaneously allowing both carrier types in a single channel poses an inherent difficulty in analyzing their individual contributions to avalanche multiplication. In ambipolar field-effect transistors (FETs), two phenomena of ambipolar transport and avalanche multiplication can occur, and both exhibit secondary rise of output current at high lateral voltage. We distinguished these two competing phenomena using the method of channel length modulation and successfully analyzed the properties of electron- and hole-initiated multiplication in ambipolar WSe FETs. Our study provides a simple and robust method to examine carrier multiplication in ambipolar materials and will foster the development of high-performance atomically thin electronic devices utilizing avalanche multiplication.
近年来，人们对二维（2D）材料中的雪崩倍增以及雪崩光电探测器和晶体管等器件应用的兴趣与日俱增。以往的研究主要使用单极半导体作为活性材料，并专注于开发高性能器件。然而，为了建立高性能电子器件和新兴架构，需要对倍增过程进行基础分析，特别是在双极材料中。尽管双极二维材料具有通过静电栅极轻松调节载流子类型的优势，但在单通道中同时允许两种载流子类型在分析它们对雪崩倍增的各自贡献时带来了固有的困难。在双极场效应晶体管（FET）中，可能会出现双极输运和雪崩倍增这两种现象，并且在高横向电压下两者都会表现出输出电流的二次上升。我们使用沟道长度调制方法区分了这两种相互竞争的现象，并成功分析了双极WSe FET中电子和空穴引发的倍增特性。我们的研究提供了一种简单而可靠的方法来研究双极材料中的载流子倍增，并将促进利用雪崩倍增的高性能原子级薄电子器件的发展。
