英国剑桥大学Chhowalla, Manish团队报道了二维过渡金属二卤族化合物的p型电触点。相关论文于2022年8月1日发表于国际顶尖学术期刊《自然》杂志上。
数字逻辑电路是基于互补金属氧化物半导体（CMOS）技术的n型和p型场效应晶体管（FET）互补对。在三维（3D或体）半导体中，受体或施主杂质的替代掺杂用于实现p型和n型FETs。然而，低维半导体的可控p型掺杂，例如二维过渡金属二卤化物（2D-TMDs），已被证明具有挑战性。虽然可以在2D TMDs上实现高质量、低电阻的n型范德华（vdW）触点，但迄今为止尚未实现将高功函数金属蒸发到2D TMDs上以获得p型器件。
该文中，研究人员报告了基于高功函数金属（如Pd和Pt）的工业兼容电子束蒸发的单层和多层二硫化钼（MoS2）和二硒化钨（WSe2）上的高性能p型器件。使用原子分辨率成像和光谱学，证明了2D TMDs和3D金属之间没有化学相互作用的接近理想的vdW界面。电子输运测量表明，费米能级未固定，基于vdW触点的p型FET在室温下表现出3.3kΩ·μm的低接触电阻，约190 cm2V-1s-1的高迁移率值，饱和电流超过>10-5安培/微米（A-μm-1），开/关比为107。研究人员还展示了一种基于n型和p型vdW触点的超薄光伏电池，其开路电压为0.6V，功率转换效率为0.82%。
附：英文原文
Title: P-type electrical contacts for two-dimensional transition metal dichalcogenides
Author: Wang, Yan, Kim, Jong Chan, Li, Yang, Ma, Kyung Yeol, Hong, Seokmo, Kim, Minsu, Shin, Hyeon Suk, Jeong, Hu Young, Chhowalla, Manish
Issue&Volume: 2022-08-01
Abstract: Digital logic circuits are based on complementary pairs of n- and p-type field effect transistors (FETs) via complementary metal oxide semiconductor (CMOS) technology. In three dimensional (3D or bulk) semiconductors, substitutional doping of acceptor or donor impurities is used to achieve p- and n-type FETs. However, the controllable p-type doping of low-dimensional semiconductors such as two-dimensional transition metal dichalcogenides (2D TMDs) has proved to be challenging. Although it is possible to achieve high quality, low resistance n-type van der Waals (vdW) contacts on 2D TMDs1–5, obtaining p-type devices from evaporating high work function metals onto 2D TMDs has not been realised so far. Here we report high-performance p-type devices on single and few-layered molybdenum disulphide (MoS2) and tungsten diselenide (WSe2) based on industry-compatible electron beam evaporation of high work function metals such as Pd and Pt. Using atomic resolution imaging and spectroscopy, we demonstrate near ideal vdW interfaces without chemical interactions between the 2D TMDs and 3D metals. Electronic transport measurements reveal that the Fermi level is unpinned and p-type FETs based on vdW contacts exhibit low contact resistance of 3.3 kΩ·μm, high mobility values of ~ 190 cm2-V-1s-1 at room temperature with saturation currents in excess of > 10-5 Amperes per micron (A-μm-1) and on/off ratio of 107. We also demonstrate an ultra-thin photovoltaic cell based on n- and p-type vdW contacts with an open circuit voltage of 0.6 V and power conversion efficiency of 0.82%.
DOI: 10.1038/s41586-022-05134-w
Source: https://www.nature.com/articles/s41586-022-05134-w